def _check_and_set_parent()

in later/unittest/backport/mock.py [0:0]


def _check_and_set_parent(parent, value, name, new_name):
    value = _extract_mock(value)

    if not _is_instance_mock(value):
        return False
    if ((value._mock_name or value._mock_new_name) or
        (value._mock_parent is not None) or
        (value._mock_new_parent is not None)):
        return False

    _parent = parent
    while _parent is not None:
        # setting a mock (value) as a child or return value of itself
        # should not modify the mock
        if _parent is value:
            return False
        _parent = _parent._mock_new_parent

    if new_name:
        value._mock_new_parent = parent
        value._mock_new_name = new_name
    if name:
        value._mock_parent = parent
        value._mock_name = name
    return True