parameters: (hub, hub_type)
return_statement: return {port: device.serial
            for (port, device) in port_device
            if device.serial}
docstring: Gets physical-port:serial# mapping for a given hub.
  
    Args:
      hub: [USBNode] Hub to get map for.
      hub_type: [usb_hubs.HubType] Which type of hub it is.
  
    Returns:
      Dict of {physical port: serial number)}
docstring_summary: Gets physical-port:serial# mapping for a given hub.
docstring_tokens: Gets physical - port : serial# mapping for a given hub .
function: def GetPhysicalPortToSerialMap(hub, hub_type):
    """Gets physical-port:serial# mapping for a given hub.
  
    Args:
      hub: [USBNode] Hub to get map for.
      hub_type: [usb_hubs.HubType] Which type of hub it is.
  
    Returns:
      Dict of {physical port: serial number)}
    """
    port_device = hub_type.GetPhysicalPortToNodeTuples(hub)
    return {port: device.serial
            for (port, device) in port_device
            if device.serial}
function_tokens: def GetPhysicalPortToSerialMap ( hub , hub_type ) : port_device = hub_type . GetPhysicalPortToNodeTuples ( hub ) return { port : device . serial for ( port , device ) in port_device if device . serial }