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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_handlers(self, room_handler=None, transaction_handler=None, user_handler=None):
 """Adds routes to Application that use specified handlers."""

        # Add all the normal matrix API routes
        if room_handler:
            room = resources.Room(room_handler,
                                  self.Api)
            self.add_route("/rooms/{room_alias}", room)
        if transaction_handler:
            transaction = resources.Transaction(transaction_handler,
                                                self.Api)
            self.add_route("/transactions/{txn_id}", transaction)
        if user_handler:
            user = resources.User(user_handler,
                                  self.Api)
            self.add_route("/users/{user_id}", user)