code: def f(s):
      
      frame = sys._getframe(1)
      d = dict(builtins.__dict__)
      d.update(frame.f_globals)
      d.update(frame.f_locals)
      return s.format_map(d)
docs: Basic support for 3.6's f-strings, in 3.5!
  
      Formats "s" using appropriate globals and locals
      dictionaries.  This f-string:
          f"hello a is {a}"
      simply becomes
          f("hello a is {a}")
      In other words, just throw parentheses around the
      string, and you're done!
  
      Implemented internally using str.format_map().
      This means it doesn't support expressions:
          f("two minus three is {2-3}")
      And it doesn't support function calls:
          f("how many elements? {len(my_list)}")
      But most other f-string features work.