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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def joint(node):
 """Merge the bodies of primal and adjoint into a single function. Args: node: A module with the primal and adjoint function definitions as returned by `reverse_ad`. Returns: func: A `Module` node with a single function definition containing the combined primal and adjoint. """

  node, _, _ = _fix(node)
  body = node.body[0].body[:-1] + node.body[1].body
  func = gast.Module(body=[gast.FunctionDef(
      name=node.body[0].name, args=node.body[1].args, body=body,
      decorator_list=[], returns=None)])
  # Clean up
  anno.clearanno(func)
  return func