networking in the client' menu dictionary because there is no self available at the class level the solution we have used is to provide wrapper functions that will get self when they are calledand which in turn call the appropriate method with the given self and any other arguments an alternative solution would be to create the call dictionary after all the methods that would allow us to create entries such as get_car_details=get_car_detailswith python able to find the get_car_details(method because the dictionary is created after the method is defined we have used the first approach since it is more explicit and does not impose an order dependency on where the dictionary is created gil although the call dictionary is only ever read after the class is createdsince it is mutable we have played it extra-safe and created lock for it to ensure that no two threads access it at the same time (againbecause of the gilthe lock isn' really needed for cpython def handle(self)sizestruct struct struct("! "size_data self rfile read(sizestruct sizesize sizestruct unpack(size_data)[ data pickle loads(self rfile read(size)trywith self calllockfunction self call[data[ ]reply function(self*data[ :]except finishreturn data pickle dumps(reply self wfile write(sizestruct pack(len(data))self wfile write(datawhenever client makes request new thread is created with new instance of the requesthandler classand then the instance' handle(method is called inside this method the data coming from the client can be read from the self rfile file objectand data can be sent back to the client by writing to the self wfile object--both of these objects are provided by socketserveropened and ready for use the struct struct is for the integer byte count that we need for the "length plus pickleformat we are using to exchange data between clients and the server we begin by reading four bytes and unpacking this as the size integer so that we know the size of the pickle we have been sent then we read size bytes and unpickle them into the data variable the read will block until the data is read in this case we know that data will always be tuplewith the first item being the requested action and the other items being the parametersbecause that is the protocol we have established with the car registration clients