code: def print_trace(f, x):
      start_node = PrintNode.new_root(x)
      trace(start_node, f, x)
      print()
  
file_path: autograd/examples/print_trace.py
imports: from __future__ import print_function
  import autograd.numpy
  from autograd.tracer import trace, Node
  from autograd import grad
label_desc: Use image node_id 2 for calling a global function with example usage: print_trace(f, x) without return types