def METHOD_NAME(**kwargs):
    """Assert that the first letters for each key are different.
    Avoids different args that start with the same first letter getting
    the same hash.
    """
    first_letters = [join_first_letters(k) for k in kwargs]
    if len(set(first_letters)) != len(first_letters):
        raise ValueError(
            f"Possible name collision! {kwargs.keys()} repeats first letters {first_letters}",
            "you can separate your arguments with underscores",
            " (delta_length -> DL, delta_width -> DW",
        )