code: def find_network_by_label(self, label):
          
          networks = self.list()
          match = [network for network in networks
                  if network.label == label]
          if not match:
              raise exc.NetworkNotFound("No network with the label '%s' exists" %
                      label)
          elif len(match) > 1:
              raise exc.NetworkLabelNotUnique("There were %s matches for the label "
                      "'%s'." % (len(match), label))
          return match[0]
docs: This is inefficient; it gets all the networks and then filters on
          the client side to find the matching name.