code: def expand_curlys(s):
      
      from functools import reduce
      curleys = list(re.finditer(r"{[^{}]*}", s))
      return reduce(_replace_curly, reversed(curleys), [s])
docs: Takes string and returns list of options:
  
      Example
      -------
      >>> expand_curlys("py{26, 27}")
      ["py26", "py27"]