def __append(self, filename, data):
    self._append_buffer[filename] = (
        self._append_buffer.get(filename, "") + data)
    self._size += len(data)
Append data to the filename's buffer without checks and flushes.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/output_writers.py/_FilePool.__append