code: def compute_mul(tree):
      """
      Compute the Variable that is the output of a multiplication tree.
  
      This is the inverse of the operation performed by `parse_mul_tree`, i.e.
      compute_mul(parse_mul_tree(tree)) == tree.
  
      Parameters
      ----------
      tree
          A multiplication tree (as output by `parse_mul_tree`).
  
      Returns
      -------
      object
          A Variable that computes the multiplication represented by the tree.
  
      """
      neg, inputs = tree
      if inputs is None:
          raise AssertionError(
              "Function `compute_mul` found a missing leaf, did you forget to "
              "call `simplify_mul` on the tree first?"
          )
      elif isinstance(inputs, list):
          # Recurse through inputs.
          rval = tensor.mul(*list(map(compute_mul, inputs)))
      else:
          rval = inputs
      if neg:
          rval = -rval
      return rval
  
imports: from __future__ import absolute_import, print_function, division
  import warnings
  import numpy
  import theano
  from theano import config, gof, printing, scalar
  from theano.compat import imap
  from theano.printing import pprint
  from theano.tensor import basic
  from theano.tensor import elemwise, opt, NotScalarConstantError
  from theano.tensor.type import values_eq_approx_remove_inf
  from theano.gof.opt import copy_stack_trace
label_desc: Use image node_id 15 for calling a global function with example usage: compute_mul(tree) and returns: rval