support copy, deepcopy in python for sorted interval lists

ortools/util/python/sorted_interval_list.cc

@@ -70,6 +70,9 @@ PYBIND11_MODULE(sorted_interval_list, m) {
            [](const Domain& domain) {
              return absl::StrCat("Domain(", domain.ToString(), ")");
            })
+      .def("__copy__", [](const Domain& self) { return Domain(self); })
+      .def("__deepcopy__",
+           [](const Domain& self, pybind11::dict) { return Domain(self); })
       // Compatibility with pre PEP8 APIs.
       .def_static("AllValues", &Domain::AllValues,
                   DOC(operations_research, Domain, AllValues))

ortools/util/python/sorted_interval_list_test.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+import copy
 from absl.testing import absltest
 from ortools.util.python import sorted_interval_list as sil
 
@@ -111,6 +113,18 @@ class SortedIntervalListTest(absltest.TestCase):
         self.assertEqual(str(d1), "[0,5]")
         self.assertEqual(repr(d1), "Domain([0,5])")
 
+    def testCopy(self):
+        d1 = sil.Domain(-3, 5)
+        d2 = copy.copy(d1)
+        self.assertIsNot(d1, d2)
+        self.assertEqual(d1.flattened_intervals(), d2.flattened_intervals())
+
+    def testDeepCopy(self):
+        d1 = sil.Domain(-3, 5)
+        d2 = copy.deepcopy(d1)
+        self.assertIsNot(d1, d2)
+        self.assertEqual(d1.flattened_intervals(), d2.flattened_intervals())
+
 
 if __name__ == "__main__":
     absltest.main()