docs: def calc_cloud_connection(self):
          """
          Add the ports and nios for a cloud connection
  
          :return: None on success or RuntimeError on error
          """
          # Connection String - SW1:1:nio_gen_eth:eth0
          # 0: Destination device 1: Destination port
          # 2: NIO 3: NIO Destination
          self.node['properties']['nios'] = []
          if self.connections is None:
              return None
          else:
              self.connections = self.connections.split(' ')
  
          for connection in sorted(self.connections):
              connection = connection.split(':')
              connection_len = len(connection)
              if connection_len == 4:
                  nio = '%s:%s' % (connection[2], connection[3])
              elif connection_len == 6:
                  nio = '%s:%s:%s:%s' % (connection[2].lower(), connection[3],
                                         connection[4], connection[5])
              else:
                  return RuntimeError('Error: Unknown connection string length '
                                      '(Length: %s)' % connection_len)
              self.node['properties']['nios'].append(nio)
              # port entry
              self.node['ports'].append({'id': self.port_id,
                                         'name': nio,
                                         'stub': True})
              self.port_id += 1
              return None