diff --git a/ortools/flatzinc/ortools.msc.in b/ortools/flatzinc/ortools.msc.in
index f954d1553d..1cc19d526b 100644
--- a/ortools/flatzinc/ortools.msc.in
+++ b/ortools/flatzinc/ortools.msc.in
@@ -8,7 +8,7 @@
   "tags": ["ortools", "cp", "lcg", "int"],
   "stdFlags": ["-a", "-f", "-p", "-r", "-s", "-v"],
   "extraFlags": [
-    ["--params", "Provide parameters interpreted as a text SatParameters proto", "string", ""],
+    ["--params", "Provide parameters interpreted as a text SatParameters proto", "string", ""]
   ],
   "supportsMzn": false,
   "supportsFzn": true,
diff --git a/ortools/java/com/google/ortools/modelbuilder/ModelSolver.java b/ortools/java/com/google/ortools/modelbuilder/ModelSolver.java
index 9016384996..bb2de343fb 100644
--- a/ortools/java/com/google/ortools/modelbuilder/ModelSolver.java
+++ b/ortools/java/com/google/ortools/modelbuilder/ModelSolver.java
@@ -119,7 +119,8 @@ public final class ModelSolver {
   }
 
   /**
-   * Checks that the solver has found a solution, and returns the ual value of the given constraint.
+   * Checks that the solver has found a solution, and returns the dual value of the given
+   * constraint.
    */
   public double getDualValue(LinearConstraint ct) {
     if (!helper.hasSolution()) {
diff --git a/ortools/linear_solver/python/model_builder.py b/ortools/linear_solver/python/model_builder.py
index 0315ef1680..427ce7a148 100644
--- a/ortools/linear_solver/python/model_builder.py
+++ b/ortools/linear_solver/python/model_builder.py
@@ -47,6 +47,7 @@ IntegerT = Union[numbers.Integral, np.integer]
 LinearExprT = Union['LinearExpr', NumberT]
 ConstraintT = Union['VarCompVar', 'BoundedLinearExpression', bool]
 ShapeT = Union[IntegerT, Sequence[IntegerT]]
+VariablesT = Union['VariableContainer', 'Variable']
 NumpyFuncT = Callable[[
     'VariableContainer',
     Optional[Union[NumberT, npt.NDArray[np.number], Sequence[NumberT]]],
@@ -578,10 +579,7 @@ class VariableContainer(mixins.NDArrayOperatorsMixin):
     def variable_indices(self) -> npt.NDArray[np.int32]:
         return self.__variable_indices
 
-    def __getitem__(
-        self,
-        pos: SliceT,
-    ) -> Union['VariableContainer', Variable]:
+    def __getitem__(self, pos: SliceT) -> VariablesT:
         # delegate the treatment of the 'pos' query to __variable_indices.
         index_or_slice: Union[np.int32, npt.NDArray[np.int32]] = (
             self.__variable_indices[pos])
@@ -590,11 +588,7 @@ class VariableContainer(mixins.NDArrayOperatorsMixin):
         else:
             return VariableContainer(self.__helper, index_or_slice)
 
-    def index_at(
-        self,
-        pos: Union[slice, int, List[int], Tuple[Union[int, slice, List[int]],
-                                                ...]],
-    ) -> Union[np.int32, npt.NDArray[np.int32]]:
+    def index_at(self, pos: SliceT) -> Union[np.int32, npt.NDArray[np.int32]]:
         """Returns the index of the variable at the position 'pos'."""
         return self.__variable_indices[pos]
 
@@ -616,6 +610,10 @@ class VariableContainer(mixins.NDArrayOperatorsMixin):
         """Returns the number of variables in the numpy array."""
         return self.__variable_indices.size
 
+    def ravel(self) -> 'VariableContainer':
+        """returns the ravel array of variables."""
+        return VariableContainer(self.__helper, self.__variable_indices.ravel())
+
     def flatten(self) -> 'VariableContainer':
         """returns the flattened array of variables."""
         return VariableContainer(self.__helper,
diff --git a/ortools/linear_solver/wrappers/model_builder_helper.cc b/ortools/linear_solver/wrappers/model_builder_helper.cc
index 8fad58ccb7..55714c698d 100644
--- a/ortools/linear_solver/wrappers/model_builder_helper.cc
+++ b/ortools/linear_solver/wrappers/model_builder_helper.cc
@@ -347,6 +347,8 @@ void ModelSolverHelper::Solve(const ModelBuilderHelper& model) {
     model_of_last_solve_ = &model.model();
     activities_.assign(model.num_constraints(),
                        std::numeric_limits<double>::quiet_NaN());
+  } else {
+    activities_.clear();
   }
 }