what does this code snippet do??

Question

can somebody give me an explanation about the following code?

from twisted.internet import protocol, reactor
from twisted.protocols import basic

class FingerProtocol(basic.LineReceiver):
    def lineReceived(self, user):
        self.transport.write(self.factory.getUser(user)+"\r\n")
        self.transport.loseConnection()

class FingerFactory(protocol.ServerFactory):
    protocol = FingerProtocol

    def __init__(self, **kwargs):  # whats is ** ??
        self.users = kwargs

    def getUser(self, user):
        return self.users.get(user, "No such user")

reactor.listenTCP(1079, FingerFactory(moshez='Happy and well'))  
# explain call to fnger factory??

Answer 1

It's keyword argument notation.

Answer 2

The call to FingerFactory (a strange name, BTW) is instantiating a FingerFactory object. The parameters to that call are passed to the __init__ function of the class, where they are accepted by the **kwargs parameter as a dictionary:

{'moshez': 'Happy and well'}

So this is assigned to the users attribute of the new FingerFactory instance.

Answer 3

And the other question, regarding FingerFactory call.

That's how you do instantiation in Python. You don't use a new keyword. You just call the class as though it were a function. The constructor of the class is __init__