docstr: Return a mock function.
code: def _mock_function(self, name="function"):
      """Return a mock function."""
      function = mock.MagicMock()
      # Either `__qualname__` or `__name__` is expected to be set for a function.
      setattr(function, "__qualname__", name)
      setattr(function, "__name__", name)
      return function
  
file_path: tfx/tfx/utils/deprecation_utils_test.py
imports: from unittest import mock
  import tensorflow
  from tfx.utils import deprecation_utils
  from tfx.utils import test_case_utils
label_desc: Use image node_id 3 for calling the DependencyUtilsTest obj's underlying member method code with example usage: obj._mock_function(name) and returns: function