parameters: (self, port, device)
docstring: Adds child to the device tree.
  
      Args:
        port: [int] Port number of the device.
        device: [USBDeviceNode] Device to add.
  
      Raises:
        ValueError: If device already has a child at the given port.
docstring_summary: Adds child to the device tree.
docstring_tokens: Adds child to the device tree .
function: def AddChild(self, port, device):
      """Adds child to the device tree.
  
      Args:
        port: [int] Port number of the device.
        device: [USBDeviceNode] Device to add.
  
      Raises:
        ValueError: If device already has a child at the given port.
      """
      if self.HasPort(port):
        raise ValueError('Duplicate port number')
      else:
        self._port_to_node[port] = device
function_tokens: def AddChild ( self , port , device ) : if self . HasPort ( port ) : raise ValueError ( 'Duplicate port number' ) else : self . _port_to_node [ port ] = device