class_docstr: A specification where kw2 gets renamed to kw3.
  
  The new API is
  
    def f(a, b, kw1, kw3): ...
code: def update_renames(self):
      self.function_keyword_renames["f"] = {"kw2": "kw3"}
  
imports: import ast
  import io
  import os
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import test
  from tensorflow.tools.compatibility import ast_edits
label_desc: Use image node_id 2 for calling the RenameKeywordSpec obj's underlying member method code with example usage: obj.update_renames() without return types