@classmethod
  def from_json(cls, json_in):
    return cls(json_in["mapper_handler_spec"],
               json_in["mapper_input_reader"],
               json_in["mapper_params"],
               json_in["mapper_shard_count"],
               json_in.get("mapper_output_writer")
              )
Creates MapperSpec from a dict-like object.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/model.py/MapperSpec.from_json