code: def default_empty(shape, dtype):
      
      default = numpy.zeros(shape, dtype=dtype)
      set_default_empty(default)
      return default
docs: Numpy's empty array can have random values in it. To prevent that, we
      define here a default emtpy array. This default empty is a numpy.zeros
      array, except that objects are set to None, and all ints to ID_NOT_SET.