class_docstr: Roll axis of an array.
class_docstr_tok: ["Roll","axis","of","an","array","."]
code: def backward(self, indexes, gy):
      axis = self.axis
      if axis < 0:
          axis += self._in_ndim
      start = self.start
      if start < 0:
          start += self._in_ndim
  
      if axis > start:
          axis += 1
      elif axis < start:
          start -= 1
  
      return Rollaxis(start, axis).apply(gy)
  
file_path: chainer/chainer/functions/array/rollaxis.py
imports: import six
  from chainer import backend
  from chainer import function_node
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the Rollaxis obj's underlying member method code with example usage: obj.backward(indexes, gy) and returns: Rollaxis