code: def _stack_weight(ws):
      # TODO(unno): Input of the current LSTM implementation is shuffled
      w = F.stack(ws, axis=1)
      shape = w.shape
      return F.reshape(w, (shape[0] * shape[1],) + shape[2:])
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  import chainer.functions
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import backend
  from chainer.testing import condition
label_desc: Use image node_id 4 for calling a global function with example usage: _stack_weight(ws) and returns: F