def METHOD_NAME():
    # If no replace_with field is given, an AssertionError will be raised
    d = {"api_server.port": 5000}
    with pytest.raises(AssertionError, match="'replace_with' must be provided."):
        rename_fields(d, "api_server.port")
    with pytest.raises(AssertionError, match="'replace_with' must be provided."):
        rename_fields(d, "api_server.port", remove_only=False)
    # If the given dictionary is not flattened, a ValueError will be raised
    d = {"a": 1, "b": {"c": 2}}
    with pytest.raises(ValueError, match="Given dictionary is not flattened. *"):
        rename_fields(d, "b.c", "b.d.c")
    # If the given dictionary is not flattened + no replace_with field is given, a ValueError will be raised
    d = {"a": 1, "b": {"c": 2}}
    with pytest.raises(ValueError, match="Given dictionary is not flattened. *"):
        rename_fields(d, "b.c")