code: def _step2byte(iterable, itemsize):
      return tuple([i * itemsize for i in iterable])
  
imports: import numpy
  import six
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  from chainer.utils import type_check
label_desc: Use image node_id 2 for calling a global function with example usage: _step2byte(iterable, itemsize) and returns: tuple