code: def persp_transformation(zfront, zback):
      a = (zfront + zback) / (zfront - zback)
      b = -2 * (zfront * zback) / (zfront - zback)
      return np.array(
          [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, a, b], [0, 0, -1, 0]]
      )
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  from six.moves import zip
  import numpy
  import numpy.linalg
label_desc: Use image node_id 7 for calling a global function with example usage: persp_transformation(zfront, zback) and returns: np