@classmethod
  def _reset_kind_map(cls):
    # Preserve "system" kinds, like __namespace__
    keep = {}
    for name, value in cls._kind_map.iteritems():
      if name.startswith('__') and name.endswith('__'):
        keep[name] = value
    cls._kind_map.clear()
    cls._kind_map.update(keep)
given radius r1, r2, find overlapping lat lons
dataset/ETHPy150Open GoogleCloudPlatform/datastore-ndb-python/ndb/model.py/Model._reset_kind_map--crossover with--dataset/ETHPy150Open sirrice/dbtruck/dbtruck/analyze/fuzzyjoin.py/dist_join