code: def opt_strip(prefix, opts):
      
  
      ret = {}
      for opt_name, opt_value in opts.items():
          # remove prefix
          if opt_name.startswith(prefix):
              opt_name = opt_name[len(prefix):]
  
          ret[opt_name] = opt_value
  
      return ret
docs: Given a dict of opts that start with prefix,
      remove the prefix from each of them.