old_contents: from typing import TypeVar
  
  __builtins__['micro_context'] = TypeVar('micro_context')
  
new_contents: 
  try:
      from typing import TypeVar
  
      __builtins__['micro_context'] = TypeVar('micro_context')
  
  except ImportError as ex:
      ''' requires python 3.5 '''
      pass
  
subject: make typing safe for pre python 3.5