def only_message_warning_format(message: str, category: str, filename: str,
    lineno: int, file: str=None, line: int=None) ->str:
    """
    Sets the standard warning message format to be:
        filename: lineno: category: message

    Parameters
    ----------
        message: str
            warning message to be printed to a user
        category: str
            type of the warning message
        filename: str
            name of the associated to the warning message
        lineno : int
            line number where the warning message was raised
        file : str
        line : str

    Returns
    -------
        formatted warning message to be printed to the console
    """
    return '{category}: {message}\n'.format(filename=filename, linenum=
        lineno, category=category.__name__, message=message)
