I am trying to use wraps to delegate a call to a decorated patch mock to another method. By examining the source code, I was able to achieve this using the (apparently undocumented) `Mock._mock_wraps` attribute instead of the `wraps` attribute which would be expected given the constructor parameter names. I find this behaviour very confusing and inconsistent. Can we either expose `Mock.wraps` attribute or document `_mock_wraps` accordingly?

Example:

class MockRepro(unittest.TestCase)

@patch('foo')
def test_side_effect(self, mock_foo):
  # Set side effect in constructor as per https://docs.python.org/3/library/unittest.mock.html#unittest.mock.Mock 
  Mock(side_effect = [1, 2])
  # Or can set on decorated patch
  foo.side_effect = [1, 2]

@patch('foo')
def test_wraps(self, mock_foo):
  def wrapped_method():
    return 3
  # Set wraps in constructor as per https://docs.python.org/3/library/unittest.mock.html#unittest.mock.Mock 
  Mock(wraps=wrapped_method)
  # Or can set on decorated patch
  foo.wraps = wrapped_method # This silently fails
  foo._mock_wraps = wrapped_method # Where does `_mock_wraps` come from?

Private attributes are not documented because they are private and subject to change.  Their use is at one's own risk.  I don't know mock well enough to understand 'inconsistent' or comment on the change proposal.