code: def show_path(from_op, tensors, sources):
      """Find one path from `from_op` to any of `tensors`, ignoring `sources`.
  
      Args:
        from_op: A `tf.Operation`.
        tensors: A `tf.Operation`, a `tf.Tensor`, or a list thereof.
        sources: A list of `tf.Tensor`.
  
      Returns:
        A python string containing the path, or "??" if none is found.
      """
      if isinstance(from_op, tensor_lib.Tensor):
          from_op = from_op.op
  
      if not isinstance(tensors, list):
          tensors = [tensors]
  
      final_ops = [_as_operation(tensor) for tensor in tensors]
  
      visited_ops = set(x.op for x in sources)
      ops_to_visit = list(final_ops)
      some_op_output = {}
      while ops_to_visit:
          op = ops_to_visit.pop()
          if op in visited_ops:
              continue
          visited_ops.add(op)
          if op == from_op:
              path_op = op
              path = [path_op]
              while path_op not in final_ops:
                  path_op = some_op_output[path_op]
                  path.append(path_op)
              return " <- ".join(
                  "%s (%s)" % (x.name, x.type) for x in reversed(path)
              )
          else:
              for inp in graph_inputs(op):
                  if inp not in visited_ops and inp not in sources:
                      some_op_output[inp] = op
                      ops_to_visit.append(inp)
      return "??"
  
imports: from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.util import object_identity
label_desc: Use image node_id 15 for calling a global function with example usage: show_path(from_op, tensors, sources) and returns: str, str