'Attach a member to balancer
:param balancer: LoadBalancer which should be used
:type  balancer: :class:`LoadBalancer`
:param member: Member to join to the balancer
:type member: :class:`Member`
:return: Member after joining the balancer.
:rtype: :class:`Member`'

def balancer_attach_member(self, balancer, member):

    node = (member.extra.get('node') or self._get_node_from_ip(member.ip))
    add_node = balancer.extra['targetpool'].add_node(node)
    if add_node:
        return self._node_to_member(node, balancer)
