'Add an extra Nic to a VM
:param  network: NetworkOffering object
:type   network: :class:\'CloudStackNetwork`
:param  node: Node Object
:type   node: :class:\'CloudStackNode`
:param  ip_address: Optional, specific IP for this Nic
:type   ip_address: ``str``
:rtype: ``bool``'

def ex_attach_nic_to_node(self, node, network, ip_address=None):

    args = {'virtualmachineid': node.id, 'networkid': network.id}
    if (ip_address is not None):
        args['ipaddress'] = ip_address
    self._async_request(command='addNicToVirtualMachine', params=args)
    return True
