docs: def port_id_from_name(port_name, device_id, nodes):
          """
          Get the port ID when given a port name
  
          :param str port_name: port name
          :param str device_id: device ID
          :param list nodes: list of nodes from :py:meth:`generate_nodes`
          :return: port ID
          :rtype: int
          """
          port_id = None
          for node in nodes:
              if device_id == node['id']:
                  for port in node['ports']:
                      if port_name == port['name']:
                          port_id = port['id']
                          break
                  break
          return port_id