'Returns the entity ID of the IdP which the ECP client should talk to
:param ipaddress: The IP address of the user client
:return: IdP entity ID or None'

def ecp_endpoint(self, ipaddress):

    _ecp = self.getattr('ecp')
    if _ecp:
        for (key, eid) in _ecp.items():
            if re.match(key, ipaddress):
                return eid
    return None
