code: def __call__(self, x):
      x = x[:, self._channel_indices, :, :]
      y = super(ParallelConvolution2D, self).__call__(x)
      ys = chainermn.functions.allgather(self.comm, y)
      return F.concat(ys, axis=1)
  
imports: from __future__ import print_function
  import chainer
  import chainer.functions
  import chainer.links
  import chainermn.functions
  import numpy
label_desc: Use image node_id 6 for calling the ParallelConvolution2D obj's underlying member method code with example usage: obj.__call__(x) and returns: F