from mock import Mock, call

mock = Mock()
arg = {}

mock(arg)
arg['el'] = 1

mock.assert_has_calls({})  # This raises assertion exception

"""
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/python37/lib/python3.7/site-packages/mock/mock.py", line 969, in assert_has_calls
    ), cause)
  File "<string>", line 3, in raise_from
AssertionError: Calls not found.
Expected: [call({})]
Actual: [call({'el': 1})]
"""