code: def test_ext_slice_roundtrip(self):
      def ext_slice(n):
          return n[:, :], n[0, :], n[:, 0]
  
      node, _ = parser.parse_entity(ext_slice, future_features=())
      source = parser.unparse(node)
      self.assertAstMatches(node, source, expr=False)
  
imports: import re
  import textwrap
  import unittest
  import gast
  from nvidia.dali._autograph.pyct import ast_util
  from nvidia.dali._autograph.pyct import errors
  from nvidia.dali._autograph.pyct import gast_util
  from nvidia.dali._autograph.pyct import parser
  from nvidia.dali._autograph.pyct import pretty_printer
label_desc: Use image node_id 25 for calling the ParserTest obj's underlying member method code with example usage: obj.test_ext_slice_roundtrip() and returns: n,  n,  n