Run the reducer on the hadoop node.

def run_reducer(self, stdin=sys.stdin, stdout=sys.stdout):
        """
        Run the reducer on the hadoop node.
        """
        self.init_hadoop()
        self.init_reducer()
        outputs = self._reduce_input(self.internal_reader((line[:-1] for line in stdin)), self.reducer, self.final_reducer)
        self.writer(outputs, stdout)