code: def parse_extras(extras_str):
      # type: (AnyStr) -> List[AnyStr]
      
  
      from pkg_resources import Requirement
  
      extras = Requirement.parse("fakepkg{0}".format(extras_to_string(extras_str))).extras
      return sorted(dedup([extra.lower() for extra in extras]))
docs: Turn a string of extras into a parsed extras list