def METHOD_NAME(self, payload):
    if self.headerLen == 27:
        # No Transfer layer
        return super(USBpcap, self).METHOD_NAME(payload)
    if self.transfer == 0:
        return USBpcapTransferIsochronous
    elif self.transfer == 1:
        return USBpcapTransferInterrupt
    elif self.transfer == 2:
        return USBpcapTransferControl
    return super(USBpcap, self).METHOD_NAME(payload)