Register all checkers of TwistedChecker to C{PyLinter}.

        @return: a list of allowed messages

def registerCheckers(self):
        """
        Register all checkers of TwistedChecker to C{PyLinter}.

        @return: a list of allowed messages
        """
        # We patch the default pylint format checker.
        patch_pylint_format.patch()

        # register checkers
        allowedMessages = list(self.allowedMessagesFromPylint)
        for strChecker in self.checkers:
            modname, classname = strChecker.split(".")
            strModule = "twistedchecker.checkers.%s" % modname
            checker = getattr(__import__(strModule,
                                        fromlist=["twistedchecker.checkers"]),
                             classname)
            instanceChecker = checker(self.linter)
            allowedMessages += list(instanceChecker.msgs.keys())
            self.linter.register_checker(instanceChecker)

        self.restrictCheckers(allowedMessages)
        return set(allowedMessages)