code: def _ortho_transformation(zfront, zback):
      # note: w component in the resulting vector will be (zback-zfront), not 1
      a = -(zfront + zback)
      b = -(zfront - zback)
      proj_matrix = np.array(
          [[2, 0, 0, 0], [0, 2, 0, 0], [0, 0, -2, 0], [0, 0, a, b]]
      )
      return proj_matrix
  
imports: import numpy
  from matplotlib import _api
label_desc: Use image node_id 10 for calling a global function with example usage: _ortho_transformation(zfront, zback) and returns: proj_matrix