def create_f4l4(cc_number):
    """Creates the token_f4l4 value if a CC number is provided.

        Parameters
            cc_number (str): The Helcim response CC number.

        Returns:
            string: the token F4L4 value.
    """
    if cc_number:
        stripped_cc = cc_number.strip()
        return '{}{}'.format(stripped_cc[:4], stripped_cc[-4:])
    return None
