class_docstr: NIN(Network In Network) architecture.
  
  The following is a list of string that can be specified to ``use_up_to`` option in ``__call__`` method;
  
  * ``'classifier'`` (default): The output of the final affine layer for classification.
  * ``'pool'``: The output of the final global average pooling.
  * ``'lastconv'``: The input of the final global average pooling without ReLU activation.
  * ``'lastconv+relu'``: Network up to ``'lastconv'`` followed by ReLU activation.
  
  References:
  
      * `Lin et al., Network In Network.
        <https://arxiv.org/abs/1312.4400>`_
code: def _input_shape(self):
      return (3, 227, 227)
  
file_path: nnabla/python/src/nnabla/models/imagenet/nin.py
imports: from __future__ import absolute_import
  from nnabla.utils.nnp_graph import NnpNetworkPass
  from .base import ImageNetBase
label_desc: Use image node_id 2 for calling the NIN obj's underlying member method code with example usage: obj._input_shape() and returns: int,  int,  int