code: def _parse_with_unset_ctx(expr_source):
      ast_node = parser.parse_expression(expr_source)
      _CtxClearer().visit(ast_node)
      return ast_node
  
imports: import types
  from absl.testing import parameterized
  import gast
  from tensorflow.python.autograph.pyct import loader
  from tensorflow.python.autograph.pyct import parser
  from tensorflow.python.autograph.pyct import qual_names
  from tensorflow.python.autograph.pyct import templates
  from tensorflow.python.platform import test
label_desc: Use image node_id 1 for calling a global function with example usage: _parse_with_unset_ctx(expr_source) and returns: ast_node