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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 get_handler(self, request):
 """ Get callable from JSON RPC request :param RPCRequest request: JSON RPC request :return: Method :rtype: callable """

        try:
            f = self._json_rpc_methods[request.method]

        except (AttributeError, KeyError):  # pragma no coverage
            raise RPCMethodError("Received invalid method '{}'".format(request.method))

        return f