code: def get_variable_trace_string(v):
      sio = StringIO()
      # For backward compatibility with old trace
      tr = getattr(v.tag, "trace", [])
      if isinstance(tr, list) and len(tr) > 0:
          print(
              " \nBacktrace when that variable is created:\n", file=sio
          )
          # The isinstance is needed to handle old pickled trace
          if isinstance(tr[0], tuple):
              traceback.print_list(v.tag.trace, sio)
          else:
              # Print separate message for each element in the list of
              # backtraces
              for idx, subtr in enumerate(tr):
                  if len(tr) > 1:
                      print("trace %d" % idx, file=sio)
                  traceback.print_list(subtr, sio)
      return sio.getvalue()
  
imports: from __future__ import absolute_import, print_function, division
  import linecache
  import sys
  import traceback
  import numpy
  from six import iteritems, integer_types, string_types, with_metaclass
  from six.moves import StringIO
  from theano import config
  from theano.compat import PY3
label_desc: Use image node_id 3 for calling a global function with example usage: get_variable_trace_string(v) and returns: sio