def __init__(self, todo_tasklet, limit):
    self._todo_tasklet = todo_tasklet
    self._limit = limit
    # A map from "options" to a list of (future, arg) tuple.
    # future is the future return from a single async operations.
    self._queues = {}
    self._running = []  # A list of in-flight todo_tasklet futures.
    self._cache = {}  # Cache of in-flight todo_tasklet futures.
Init.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/ndb/context.py/AutoBatcher.__init__