code: def _lower_if_str(item):
      
      # python 2 / 3 shill
      try:
          string_type = basestring
      except NameError:
          string_type = str
  
      if isinstance(item, string_type):
          return item.lower()
  
      return item
docs: Try to convert item to lowercase, if it is string.
  
      Args:
          item (obj): Str, unicode or any other object.
  
      Returns:
          obj: ``item.lower()`` if `item` is ``str`` or ``unicode``, else just \
               `item` itself.