code: def test_printing_scan():
      # Skip test if pydot is not available.
      if not theano.printing.pydot_imported:
          raise SkipTest("pydot not available")
  
      def f_pow2(x_tm1):
          return 2 * x_tm1
  
      state = theano.tensor.scalar("state")
      n_steps = theano.tensor.iscalar("nsteps")
      output, updates = theano.scan(
          f_pow2,
          [],
          state,
          [],
          n_steps=n_steps,
          truncate_gradient=-1,
          go_backwards=False,
      )
      f = theano.function(
          [state, n_steps],
          output,
          updates=updates,
          allow_input_downcast=True,
      )
      theano.printing.pydotprint(output, scan_graphs=True)
      theano.printing.pydotprint(f, scan_graphs=True)
  
imports: from __future__ import absolute_import, print_function, division
  import logging
  from nose.plugins.skip import SkipTest
  import numpy
  from six.moves import StringIO
  import theano
  import theano.tensor
  from theano.printing import min_informative_str, debugprint
label_desc: Use image node_id 12 for calling a global function with example usage: test_printing_scan() and returns: unknown