original_string: private function _key($identifier) {
      	extract($identifier);
      	$arg_string = "";
      	return md5(serialize($class . $method . implode('~', $args)));
      }
code: private function _key($identifier) {
      	extract($identifier);
      	$arg_string = "";
      	return md5(serialize($class . $method . implode('~', $args)));
      }
code_tokens: private function _key ( $ identifier ) { extract ( $ identifier ) ; $ arg_string = "" ; return md5 ( serialize ( $ class . $ method . implode ( '~' , $ args ) ) ) ; }
docstring: Creates a key for cached class methods
  @param  array $identifier  class|method|args
  @return string
docstring_tokens: Creates a key for cached class methods