Fix invalid escape sequence

pandas/tests/internals/test_internals.py

@@ -1249,7 +1249,7 @@ def test_binop_other(self, op, value, dtype):
             else:
                 msg = (
                     re.escape(
-                        f"cannot perform __{op.__name__}_\_ with this index type: "
+                        f"cannot perform __{op.__name__}__ with this index type: "
                     )
                     + "(DatetimeArray|TimedeltaArray)"
                 )