code: def do_cleaning(self, arg):
          
          if arg is not None:
              if isinstance(arg, list):
                  newlist = []
                  for entry in arg:
                      newlist.append(self.do_cleaning(entry))
                  return newlist
              else:
                  if sys.version_info[0] < 3:
                      arg = unicode(arg)
                  else:
                      arg = str(arg)
                  arg = self.delete_tags(arg)
                  arg = self.delete_whitespaces(arg)
                  return arg
          else:
              return None
docs: Does the actual cleaning by using the delete methods above.
  
          :param arg: A string, the string which shell be cleaned. Or a list, in which case each of the strings within the
          list is cleaned.
          :return: A string, the cleaned string. Or a list with cleaned string entries.