As reported on StackOverflow:
https://stackoverflow.com/questions/57636747/how-to-perform-assert-has-calls-for-a-getitem-call

The following code would output: [call(), call().foo(), call().foo().__getitem__('bar')]

from unittest.mock import MagicMock, call
mm = MagicMock()
mm().foo()['bar']
print(mm.mock_calls)

but trying to use that list with mm.assert_has_calls([call(), call().foo(), call().foo().__getitem__('bar')]) would result in:

TypeError: tuple indices must be integers or slices, not str