code: def visit(self, node):
      super(_CtxClearer, self).visit(node)
      if hasattr(node, "ctx"):
          node.ctx = None
      return node
  
imports: import imp
  import unittest
  import gast
  from nvidia.dali._autograph.pyct import gast_util
  from nvidia.dali._autograph.pyct import loader
  from nvidia.dali._autograph.pyct import parser
  from nvidia.dali._autograph.pyct import qual_names
  from nvidia.dali._autograph.pyct import templates
label_desc: Use image node_id 1 for calling the _CtxClearer obj's underlying member method code with example usage: obj.visit(node) and returns: node