Error when I try to assign a member to a Pool

When I execute this piece of code:

pool = bigip.tm.ltm.pools.pool.create(name="Pool Name",
                                      partition='Common',
                                      description="First Pool",
                                      monitor="/Common/" + monitor.name)

Create the Members
node = pool.members_s.members.create(name="Node name",
                                     address=ip_address,
                                     partition='Common',
                                     description='First Node',
                                     monitor="/Common/icmp_tid")

 UpdatePool
pool.update()

I get the next error: Text: '{"code":400,"message":"01070587:7: The requested monitor rule (/Common/icmp_tid on pool ) can only be applied to node addresses. Can anyone explain what is the issue? When I try to create the node itself with th command mgmt.tm.ltm.nodes.node.create() and attach the monitor to it I don't have any problem. But when I create it as a member of an existing pool the error appears.

Is there any way this can work or is there any way of assigning an existing node as a member of an pool?

Thanks