code: def _ij_ik_jkl_to_il(a, b, c):
      ab = chainer.functions.matmul(a[:, :, None], b[:, None, :])  # ijk
      c = c.reshape(-1, c.shape[-1])  # [jk]l
      return chainer.functions.matmul(_as_mat(ab), c)
  
imports: import numpy
  import chainer
  from chainer import backend
  from chainer import function_node
  from chainer.utils import type_check
label_desc: Use image node_id 3 for calling a global function with example usage: _ij_ik_jkl_to_il(a, b, c) and returns: chainer