diff --git a/ortools/math_opt/core/c_api/cpp_example_test.py b/ortools/math_opt/core/c_api/cpp_example_test.py
index ca3516314e..457f27678f 100644
--- a/ortools/math_opt/core/c_api/cpp_example_test.py
+++ b/ortools/math_opt/core/c_api/cpp_example_test.py
@@ -27,6 +27,7 @@ class CppExampleTest(
     log_scraping.LogScraping,
     absltest.TestCase,
 ):
+
     def test_regression(self):
         result = self.assert_binary_succeeds("ortools/math_opt/core/c_api/cpp_example")
         is_optimal = self.assert_has_line_with_prefixed_number(
diff --git a/ortools/math_opt/core/python/solver_gurobi_test.py b/ortools/math_opt/core/python/solver_gurobi_test.py
index 6d925135af..c049e6babd 100644
--- a/ortools/math_opt/core/python/solver_gurobi_test.py
+++ b/ortools/math_opt/core/python/solver_gurobi_test.py
@@ -96,6 +96,7 @@ def _expected_iis_success() -> (
 class PybindComputeInfeasibleSubsystemTest(
     compare_proto.MathOptProtoAssertions, absltest.TestCase
 ):
+
     def test_compute_infeasible_subsystem_infeasible(self) -> None:
         iis_result = solver.compute_infeasible_subsystem(
             _simple_infeasible_model(),
diff --git a/ortools/math_opt/core/python/solver_test.py b/ortools/math_opt/core/python/solver_test.py
index f66f6d52c2..5e247c3e35 100644
--- a/ortools/math_opt/core/python/solver_test.py
+++ b/ortools/math_opt/core/python/solver_test.py
@@ -84,6 +84,7 @@ def _solve_model(
 
 
 class PybindSolverTest(parameterized.TestCase):
+
     def tearDown(self):
         super().tearDown()
         self.assertEqual(solver.debug_num_solver(), 0)
@@ -261,6 +262,7 @@ class PybindSolverTest(parameterized.TestCase):
 
 
 class PybindSolveInterrupterTest(parameterized.TestCase):
+
     def test_solve_interrupter_is_interrupted(self) -> None:
         interrupter = solver.SolveInterrupter()
         self.assertFalse(interrupter.is_interrupted())
diff --git a/ortools/math_opt/python/callback_test.py b/ortools/math_opt/python/callback_test.py
index 5b47fab589..b2058a4e7f 100644
--- a/ortools/math_opt/python/callback_test.py
+++ b/ortools/math_opt/python/callback_test.py
@@ -25,6 +25,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class CallbackDataTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_parse_callback_data_no_solution(self) -> None:
         mod = model.Model(name="test_model")
         cb_data_proto = callback_pb2.CallbackDataProto(
@@ -86,6 +87,7 @@ class CallbackDataTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
 
 
 class CallbackRegistrationTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def testToProto(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
@@ -123,6 +125,7 @@ class CallbackRegistrationTest(compare_proto.MathOptProtoAssertions, absltest.Te
 class GeneratedLinearConstraintTest(
     compare_proto.MathOptProtoAssertions, absltest.TestCase
 ):
+
     def testToProto(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
@@ -148,6 +151,7 @@ class GeneratedLinearConstraintTest(
 
 
 class CallbackResultTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def testToProto(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
diff --git a/ortools/math_opt/python/compute_infeasible_subsystem_result_test.py b/ortools/math_opt/python/compute_infeasible_subsystem_result_test.py
index a578f87739..5ce1187eba 100644
--- a/ortools/math_opt/python/compute_infeasible_subsystem_result_test.py
+++ b/ortools/math_opt/python/compute_infeasible_subsystem_result_test.py
@@ -29,6 +29,7 @@ _ComputeInfeasibleSubsystemResult = (
 
 
 class ModelSubsetBoundsTest(absltest.TestCase, compare_proto.MathOptProtoAssertions):
+
     def test_empty(self) -> None:
         self.assertTrue(_ModelSubsetBounds().empty())
         self.assertFalse(_ModelSubsetBounds(lower=True).empty())
@@ -61,6 +62,7 @@ class ModelSubsetBoundsTest(absltest.TestCase, compare_proto.MathOptProtoAsserti
 
 
 class ModelSubsetTest(absltest.TestCase, compare_proto.MathOptProtoAssertions):
+
     def test_empty(self) -> None:
         m = model.Model()
         x = m.add_binary_variable()
@@ -168,6 +170,7 @@ class ModelSubsetTest(absltest.TestCase, compare_proto.MathOptProtoAssertions):
 
 
 class ComputeInfeasibleSubsystemResultTest(absltest.TestCase):
+
     def test_to_proto_round_trip(self) -> None:
         m = model.Model()
         x = m.add_binary_variable()
diff --git a/ortools/math_opt/python/expressions_test.py b/ortools/math_opt/python/expressions_test.py
index d8cd2770c9..d1bd3b1a50 100644
--- a/ortools/math_opt/python/expressions_test.py
+++ b/ortools/math_opt/python/expressions_test.py
@@ -23,6 +23,7 @@ def _type_check_linear_sum(x: model.LinearSum) -> None:
 
 
 class FastSumTest(absltest.TestCase):
+
     def test_variables(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable()
@@ -79,6 +80,7 @@ class FastSumTest(absltest.TestCase):
 
 
 class EvaluateExpressionTest(absltest.TestCase):
+
     def test_scalar_expression(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable()
diff --git a/ortools/math_opt/python/hash_model_storage_test.py b/ortools/math_opt/python/hash_model_storage_test.py
index 5423fde0c4..2b6c8efe18 100644
--- a/ortools/math_opt/python/hash_model_storage_test.py
+++ b/ortools/math_opt/python/hash_model_storage_test.py
@@ -19,6 +19,7 @@ from ortools.math_opt.python import hash_model_storage
 
 
 class HashModelStorageTest(absltest.TestCase):
+
     def test_quadratic_term_storage(self):
         storage = hash_model_storage._QuadraticTermStorage()
         storage.set_coefficient(0, 1, 1.0)
diff --git a/ortools/math_opt/python/ipc/proto_converter_test.py b/ortools/math_opt/python/ipc/proto_converter_test.py
index 5fbca2be02..c8b4cee0f4 100644
--- a/ortools/math_opt/python/ipc/proto_converter_test.py
+++ b/ortools/math_opt/python/ipc/proto_converter_test.py
@@ -45,6 +45,7 @@ def _simple_request() -> rpc_pb2.SolveRequest:
 
 
 class ProtoConverterTest(absltest.TestCase, compare.Proto2Assertions):
+
     def test_convert_request(self):
         request = _simple_request()
         expected = optimization_pb2.SolveMathOptModelRequest(
diff --git a/ortools/math_opt/python/ipc/remote_http_solve_test.py b/ortools/math_opt/python/ipc/remote_http_solve_test.py
index 23b20e9250..d6ac93ff91 100644
--- a/ortools/math_opt/python/ipc/remote_http_solve_test.py
+++ b/ortools/math_opt/python/ipc/remote_http_solve_test.py
@@ -77,6 +77,7 @@ def _simple_model() -> tuple[mathopt.Model, mathopt.Variable, mathopt.Variable]:
 
 
 class RemoteHttpSolveTest(absltest.TestCase):
+
     def test_session_headers(self):
         deadline = 1.0
         server_deadline = deadline * (1 - remote_http_solve._RELATIVE_TIME_BUFFER)
diff --git a/ortools/math_opt/python/linear_expression_test.py b/ortools/math_opt/python/linear_expression_test.py
index 96fcea060c..29e6124b23 100644
--- a/ortools/math_opt/python/linear_expression_test.py
+++ b/ortools/math_opt/python/linear_expression_test.py
@@ -37,6 +37,7 @@ _QUADRATIC_TYPES = (
 
 
 class BoundedExprTest(absltest.TestCase):
+
     def test_eq_float(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -334,6 +335,7 @@ class BoundedExprTest(absltest.TestCase):
 
 
 class BoundedExprErrorTest(absltest.TestCase):
+
     def test_ne(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -589,6 +591,7 @@ class BoundedExprErrorTest(absltest.TestCase):
 
 
 class BoundedExprStrAndReprTest(absltest.TestCase):
+
     def test_upper_bounded_expr(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -628,6 +631,7 @@ class BoundedExprStrAndReprTest(absltest.TestCase):
 
 # TODO(b/216492143): change __str__ to match C++ implementation in cl/421649402.
 class LinearStrAndReprTest(parameterized.TestCase):
+
     def test_sorting_ok(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -720,6 +724,7 @@ class LinearStrAndReprTest(parameterized.TestCase):
 
 # TODO(b/216492143): change __str__ to match C++ implementation in cl/421649402.
 class QuadraticStrAndReprTest(parameterized.TestCase):
+
     def test_sorting_ok(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -858,6 +863,7 @@ def all_linear_number_op_parameters() -> List[LinearNumberOpTestsParameters]:
 
 # Test all operations (including inplace) between a number and a Linear object
 class LinearNumberOpTests(parameterized.TestCase):
+
     @parameterized.named_parameters(
         (p.test_suffix(), p.linear_type, p.constant, p.linear_first)
         for p in all_linear_number_op_parameters()
@@ -1087,6 +1093,7 @@ class LinearNumberOpTests(parameterized.TestCase):
 
 
 class QuadraticTermKey(absltest.TestCase):
+
     # Mock QuadraticTermKey.__hash__ to have a collision in the dictionary lookup
     # so that a correct behavior of term1 == term2 is needed to recover the
     # values. For instance, if QuadraticTermKey.__eq__ only compared equality of
@@ -1141,6 +1148,7 @@ def all_quadratic_number_op_parameters() -> List[QuadraticNumberOpTestsParameter
     for p in all_quadratic_number_op_parameters()
 )
 class QuadraticNumberOpTests(parameterized.TestCase):
+
     def test_mult(
         self,
         quadratic_type: str,
@@ -1436,6 +1444,7 @@ def all_linear_linear_add_sub_params() -> List[LinearLinearAddSubTestParams]:
 
 # Test add/sub operations (including inplace) between two Linear objects.
 class LinearLinearAddSubTest(parameterized.TestCase):
+
     @parameterized.named_parameters(
         (p.test_suffix(), p.lhs_type, p.rhs_type, p.subtract)
         for p in all_linear_linear_add_sub_params()
@@ -1543,6 +1552,7 @@ def all_linear_quadratic_add_sub_params() -> List[LinearQuadraticAddSubTestParam
 # objects. Also re-checks the operations for the pure Linear check when the
 # result is intereted as a QuadraticExpression.
 class LinearQuadraticAddSubTest(parameterized.TestCase):
+
     def assertDictEqualWithZeroDefault(
         self, dict1: dict[Any, float], dict2: dict[Any, float]
     ) -> None:
@@ -1710,6 +1720,7 @@ class LinearQuadraticAddSubTest(parameterized.TestCase):
 
 # Test multiplication of two Linear objects.
 class LinearLinearMulTest(parameterized.TestCase):
+
     def assertDictEqualWithZeroDefault(
         self, dict1: dict[Any, float], dict2: dict[Any, float]
     ) -> None:
@@ -2038,6 +2049,7 @@ class LinearLinearMulTest(parameterized.TestCase):
 
 # Test negate on Linear and Quadratic objects.
 class NegateTest(parameterized.TestCase):
+
     def test_negate_var(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -2230,6 +2242,7 @@ def get_linear_or_quadratic_for_unsupported_operand_test(
 
 
 class UnsupportedProductOperandTest(parameterized.TestCase):
+
     @parameterized.named_parameters(
         (p.test_suffix(), p.lhs_type, p.rhs_type)
         for p in all_unsupported_product_operand_params()
@@ -2308,6 +2321,7 @@ def all_unsupported_addition_operand_params() -> (
     for p in all_unsupported_addition_operand_params()
 )
 class UnsupportedAdditionOperandTest(parameterized.TestCase):
+
     def test_add(
         self, linear_or_quadratic_type: str, linear_or_quadratic_first: bool
     ) -> None:
@@ -2382,6 +2396,7 @@ class UnsupportedAdditionOperandTest(parameterized.TestCase):
 
 
 class UnsupportedInitializationTest(parameterized.TestCase):
+
     def test_linear_sum_not_tuple(self):
         # pytype: disable=wrong-arg-types
         with self.assertRaisesRegex(TypeError, "object is not iterable"):
@@ -2469,6 +2484,7 @@ class UnsupportedInitializationTest(parameterized.TestCase):
 
 @parameterized.named_parameters(("_python_sum", True), ("LinearSum", False))
 class SumTest(parameterized.TestCase):
+
     def test_sum_vars(self, python_sum: bool) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
@@ -2637,6 +2653,7 @@ class SumTest(parameterized.TestCase):
 
 
 class AstTest(parameterized.TestCase):
+
     def assertDictEqualWithZeroDefault(
         self, dict1: dict[Any, float], dict2: dict[Any, float]
     ) -> None:
@@ -2739,6 +2756,7 @@ class AstTest(parameterized.TestCase):
 # Test behavior of LinearExpression and as_flat_linear_expression that is
 # not covered by other tests.
 class LinearExpressionTest(absltest.TestCase):
+
     def test_init_to_zero(self) -> None:
         expression = model.LinearExpression()
         self.assertEqual(expression.offset, 0.0)
@@ -2775,6 +2793,7 @@ class LinearExpressionTest(absltest.TestCase):
 # Test behavior of QuadraticExpression and as_flat_quadratic_expression that is
 # not covered by other tests.
 class QuadraticExpressionTest(absltest.TestCase):
+
     def test_terms_read_only(self) -> None:
         mod = model.Model()
         x = mod.add_binary_variable(name="x")
diff --git a/ortools/math_opt/python/mathopt_test.py b/ortools/math_opt/python/mathopt_test.py
index 0858500434..259e3e8e1f 100644
--- a/ortools/math_opt/python/mathopt_test.py
+++ b/ortools/math_opt/python/mathopt_test.py
@@ -84,6 +84,7 @@ def _get_public_api(module: types.ModuleType) -> List[Tuple[str, Any]]:
 
 
 class MathoptTest(absltest.TestCase):
+
     def test_imports(self) -> None:
         missing_imports: List[str] = []
         for module in _MODULES_TO_CHECK:
diff --git a/ortools/math_opt/python/message_callback_test.py b/ortools/math_opt/python/message_callback_test.py
index 7e97c947f8..7c8daaa231 100644
--- a/ortools/math_opt/python/message_callback_test.py
+++ b/ortools/math_opt/python/message_callback_test.py
@@ -24,8 +24,10 @@ from ortools.math_opt.python import message_callback
 
 
 class PrinterMessageCallbackTest(absltest.TestCase):
+
     def test_no_prefix(self):
         class FlushCountingStringIO(io.StringIO):
+
             def __init__(self):
                 super().__init__()
                 self.num_flushes: int = 0
@@ -54,6 +56,7 @@ class PrinterMessageCallbackTest(absltest.TestCase):
 
 
 class LogMessagesTest(absltest.TestCase):
+
     def test_defaults(self):
         with self.assertLogs(logger="absl", level="INFO") as logs:
             message_callback.log_messages(["line 1", "line 2"])
@@ -111,6 +114,7 @@ class VLogMessagesTest(absltest.TestCase):
 
 
 class ListMessageCallbackTest(absltest.TestCase):
+
     def test_empty(self):
         msgs = []
         cb = message_callback.list_message_callback(msgs)
diff --git a/ortools/math_opt/python/model_parameters_test.py b/ortools/math_opt/python/model_parameters_test.py
index f17f597ef9..14188ac41e 100644
--- a/ortools/math_opt/python/model_parameters_test.py
+++ b/ortools/math_opt/python/model_parameters_test.py
@@ -24,6 +24,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class ModelParametersTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_solution_hint_round_trip(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
diff --git a/ortools/math_opt/python/model_storage.py b/ortools/math_opt/python/model_storage.py
index 881bc08fcb..1086254825 100644
--- a/ortools/math_opt/python/model_storage.py
+++ b/ortools/math_opt/python/model_storage.py
@@ -117,6 +117,7 @@ class StorageUpdateTracker(abc.ABC):
 
 
 class UsedUpdateTrackerAfterRemovalError(RuntimeError):
+
     def __init__(self):
         super().__init__(
             "Attempted to use update tracker after removing it from model storage."
diff --git a/ortools/math_opt/python/model_storage_test.py b/ortools/math_opt/python/model_storage_test.py
index 49849f2354..b8c5e23da7 100644
--- a/ortools/math_opt/python/model_storage_test.py
+++ b/ortools/math_opt/python/model_storage_test.py
@@ -30,6 +30,7 @@ _ObjEntry = model_storage.LinearObjectiveEntry
 
 @parameterized.parameters((hash_model_storage.HashModelStorage,))
 class ModelStorageTest(compare_proto.MathOptProtoAssertions, parameterized.TestCase):
+
     def test_add_and_read_variables(self, storage_class: _StorageClass) -> None:
         storage = storage_class("test_model")
         self.assertEqual(0, storage.next_variable_id())
diff --git a/ortools/math_opt/python/model_storage_update_test.py b/ortools/math_opt/python/model_storage_update_test.py
index 269d3d9914..e7614ad92c 100644
--- a/ortools/math_opt/python/model_storage_update_test.py
+++ b/ortools/math_opt/python/model_storage_update_test.py
@@ -36,6 +36,7 @@ _ObjectiveUpdatesProto = model_update_pb2.ObjectiveUpdatesProto
 
 @parameterized.parameters((hash_model_storage.HashModelStorage,))
 class ModelStorageTest(compare_proto.MathOptProtoAssertions, parameterized.TestCase):
+
     def test_simple_delete_var(self, storage_class: _StorageClass) -> None:
         storage = storage_class("test_model")
         tracker = storage.add_update_tracker()
diff --git a/ortools/math_opt/python/model_test.py b/ortools/math_opt/python/model_test.py
index 59afae5410..6cd057db06 100644
--- a/ortools/math_opt/python/model_test.py
+++ b/ortools/math_opt/python/model_test.py
@@ -32,6 +32,7 @@ _ObjEntry = model_storage.LinearObjectiveEntry
 
 @parameterized.parameters((hash_model_storage.HashModelStorage,))
 class ModelTest(compare_proto.MathOptProtoAssertions, parameterized.TestCase):
+
     def test_name(self, storage_class: StorageClass) -> None:
         mod = model.Model(name="test_model", storage_class=storage_class)
         self.assertEqual("test_model", mod.name)
diff --git a/ortools/math_opt/python/normalize_test.py b/ortools/math_opt/python/normalize_test.py
index 95300d9dcd..750f0aaa30 100644
--- a/ortools/math_opt/python/normalize_test.py
+++ b/ortools/math_opt/python/normalize_test.py
@@ -26,6 +26,7 @@ from ortools.math_opt.python import normalize
 
 
 class MathOptProtoAssertionsTest(absltest.TestCase, compare.Proto2Assertions):
+
     def test_removes_empty_message(self) -> None:
         model_with_empty_vars = model_pb2.ModelProto()
         model_with_empty_vars.variables.SetInParent()
diff --git a/ortools/math_opt/python/parameters_test.py b/ortools/math_opt/python/parameters_test.py
index 9dad699a6e..f283cedc57 100644
--- a/ortools/math_opt/python/parameters_test.py
+++ b/ortools/math_opt/python/parameters_test.py
@@ -31,6 +31,7 @@ from ortools.sat import sat_parameters_pb2
 
 
 class GurobiParameters(absltest.TestCase):
+
     def test_to_proto(self) -> None:
         gurobi_proto = parameters.GurobiParameters(
             param_values={"x": "dog", "ab": "7"}
@@ -45,6 +46,7 @@ class GurobiParameters(absltest.TestCase):
 
 
 class GlpkParameters(absltest.TestCase):
+
     def test_to_proto(self) -> None:
         # Test with `optional bool` set to true.
         glpk_proto = parameters.GlpkParameters(
@@ -71,6 +73,7 @@ class GlpkParameters(absltest.TestCase):
 
 
 class ProtoRoundTrip(absltest.TestCase):
+
     def test_solver_type_round_trip(self) -> None:
         for solver_type in parameters.SolverType:
             self.assertEqual(
diff --git a/ortools/math_opt/python/result_test.py b/ortools/math_opt/python/result_test.py
index cc35d4e1e6..6c4e7beeb1 100644
--- a/ortools/math_opt/python/result_test.py
+++ b/ortools/math_opt/python/result_test.py
@@ -26,6 +26,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class ParseTerminationReason(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_termination_unspecified(self) -> None:
         termination_proto = result_pb2.TerminationProto(
             reason=result_pb2.TERMINATION_REASON_UNSPECIFIED
@@ -86,6 +87,7 @@ class ParseTerminationReason(compare_proto.MathOptProtoAssertions, absltest.Test
 
 
 class ParseProblemStatus(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_problem_status_round_trip(self) -> None:
         problem_status = result.ProblemStatus(
             primal_status=result.FeasibilityStatus.FEASIBLE,
@@ -124,6 +126,7 @@ class ParseProblemStatus(compare_proto.MathOptProtoAssertions, absltest.TestCase
 
 
 class ParseObjectiveBounds(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_objective_bounds_round_trip(self) -> None:
         objective_bounds = result.ObjectiveBounds(primal_bound=10, dual_bound=20)
         objective_bounds_proto = objective_bounds.to_proto()
@@ -136,6 +139,7 @@ class ParseObjectiveBounds(compare_proto.MathOptProtoAssertions, absltest.TestCa
 
 
 class ParseSolveStats(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_problem_status_round_trip(self) -> None:
         solve_stats = result.SolveStats(
             solve_time=datetime.timedelta(seconds=10),
@@ -157,6 +161,7 @@ class ParseSolveStats(compare_proto.MathOptProtoAssertions, absltest.TestCase):
 
 
 class SolveResultAuxiliaryFunctionsTest(absltest.TestCase):
+
     def test_solve_time(self) -> None:
         res = result.SolveResult(
             solve_stats=result.SolveStats(solve_time=datetime.timedelta(seconds=10))
@@ -638,6 +643,7 @@ def _make_undetermined_result_proto() -> result_pb2.SolveResultProto:
 
 
 class SolveResultTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_solve_result_gscip_output(self) -> None:
         mod = model.Model(name="test_model")
         mod.add_binary_variable()
diff --git a/ortools/math_opt/python/solution_test.py b/ortools/math_opt/python/solution_test.py
index 7c481e0af6..bc56918d3a 100644
--- a/ortools/math_opt/python/solution_test.py
+++ b/ortools/math_opt/python/solution_test.py
@@ -20,6 +20,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class ParsePrimalSolutionTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_empty_primal_solution_proto_round_trip(self) -> None:
         mod = model.Model(name="test_model")
         empty_solution = solution.PrimalSolution(
@@ -64,6 +65,7 @@ class ParsePrimalSolutionTest(compare_proto.MathOptProtoAssertions, absltest.Tes
 
 
 class ParsePrimalRayTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_parse(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
@@ -76,6 +78,7 @@ class ParsePrimalRayTest(compare_proto.MathOptProtoAssertions, absltest.TestCase
 
 
 class ParseDualSolutionTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_empty_primal_solution_proto_round_trip(self) -> None:
         mod = model.Model(name="test_model")
         empty_solution = solution.DualSolution(
@@ -137,6 +140,7 @@ class ParseDualSolutionTest(compare_proto.MathOptProtoAssertions, absltest.TestC
 
 
 class ParseDualRayTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_parse(self) -> None:
         mod = model.Model(name="test_model")
         x = mod.add_binary_variable(name="x")
@@ -154,6 +158,7 @@ class ParseDualRayTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
 
 
 class BasisTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_empty_basis_proto_round_trip(self) -> None:
         mod = model.Model(name="test_model")
         empty_basis = solution.Basis()
@@ -268,6 +273,7 @@ class BasisTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
 
 
 class ParseSolutionTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_solution_proto_round_trip(self) -> None:
         mod = model.Model(name="test_model")
         mod.add_variable()
diff --git a/ortools/math_opt/python/solve_gurobi_test.py b/ortools/math_opt/python/solve_gurobi_test.py
index afa1703306..19b201e008 100644
--- a/ortools/math_opt/python/solve_gurobi_test.py
+++ b/ortools/math_opt/python/solve_gurobi_test.py
@@ -31,6 +31,7 @@ _Bounds = compute_infeasible_subsystem_result.ModelSubsetBounds
 
 
 class SolveTest(absltest.TestCase):
+
     def test_callback(self) -> None:
         mod = model.Model(name="test_model")
         # Solve the problem:
diff --git a/ortools/math_opt/python/solve_test.py b/ortools/math_opt/python/solve_test.py
index 42d561f089..6fcefa2759 100644
--- a/ortools/math_opt/python/solve_test.py
+++ b/ortools/math_opt/python/solve_test.py
@@ -46,6 +46,7 @@ def _list_is_near(v1: List[float], v2: List[float], tolerance: float = 1e-5) ->
 
 
 class SolveTest(absltest.TestCase):
+
     def _assert_dict_almost_equal(
         self, expected: VarOrConstraintDict, actual: VarOrConstraintDict, places=5
     ):
diff --git a/ortools/math_opt/python/solver_resources_test.py b/ortools/math_opt/python/solver_resources_test.py
index 455be29d25..9685f5f72a 100644
--- a/ortools/math_opt/python/solver_resources_test.py
+++ b/ortools/math_opt/python/solver_resources_test.py
@@ -21,6 +21,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class SolverResourcesTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_to_proto_empty(self):
         self.assert_protos_equiv(
             solver_resources.SolverResources().to_proto(),
diff --git a/ortools/math_opt/python/sparse_containers_test.py b/ortools/math_opt/python/sparse_containers_test.py
index 55b1fb492f..2851631708 100644
--- a/ortools/math_opt/python/sparse_containers_test.py
+++ b/ortools/math_opt/python/sparse_containers_test.py
@@ -20,6 +20,7 @@ from ortools.math_opt.python.testing import compare_proto
 
 
 class SparseDoubleVectorTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_to_proto_empty(self) -> None:
         actual = sparse_containers.to_sparse_double_vector_proto({})
         self.assert_protos_equiv(
@@ -97,6 +98,7 @@ class SparseDoubleVectorTest(compare_proto.MathOptProtoAssertions, absltest.Test
 
 
 class SparseInt32VectorTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_to_proto_empty(self) -> None:
         self.assert_protos_equiv(
             sparse_containers.to_sparse_int32_vector_proto({}),
@@ -124,6 +126,7 @@ class SparseInt32VectorTest(compare_proto.MathOptProtoAssertions, absltest.TestC
 
 
 class SparseVectorFilterTest(compare_proto.MathOptProtoAssertions, absltest.TestCase):
+
     def test_is_none(self) -> None:
         f = sparse_containers.SparseVectorFilter(skip_zero_values=True)
         self.assertTrue(f.skip_zero_values)
diff --git a/ortools/math_opt/python/statistics_test.py b/ortools/math_opt/python/statistics_test.py
index b2fc6ca8ff..f6d5129d8f 100644
--- a/ortools/math_opt/python/statistics_test.py
+++ b/ortools/math_opt/python/statistics_test.py
@@ -22,6 +22,7 @@ from ortools.math_opt.python import statistics
 
 
 class RangeTest(absltest.TestCase):
+
     def test_merge_optional_ranges(self) -> None:
         self.assertIsNone(statistics.merge_optional_ranges(None, None))
         r = statistics.Range(1.0, 3.0)
@@ -52,6 +53,7 @@ class RangeTest(absltest.TestCase):
 
 
 class ModelRangesTest(absltest.TestCase):
+
     def test_printing(self) -> None:
         self.assertMultiLineEqual(
             str(
@@ -130,6 +132,7 @@ class ModelRangesTest(absltest.TestCase):
 
 
 class ComputeModelRangesTest(absltest.TestCase):
+
     def test_empty(self) -> None:
         mdl = model.Model(name="model")
         self.assertEqual(