Check are we authorised
    :return: True if we authorised
        False if no auth provided
        exception if provided auth is wrong

def check_auth():
    """
    Check are we authorised
    :return: True if we authorised
        False if no auth provided
        exception if provided auth is wrong
    """
    if get_oauth_token():
        auth_info = get_auth_info()
        if not auth_info:
            raise MissingTokenInfoException("Could not get token info")
        if datetime.now() >= auth_info['expires_at']:
            msg = (
                'Token is expired. Now %s but valid until %s',
                datetime.now(), auth_info['expires_at']
            )

            log.warn(
                msg[0], *msg[1:]
            )
            raise TokenIsExpired(msg[0] % msg[1:])
    else:
        raise MissingTokenException()