original_string: public static function extract($string, $offset, $length = null) {
          if ($length) {
              return mb_substr($string, $offset, $length);
          }
  
          return mb_substr($string, $offset);
      }
code: public static function extract($string, $offset, $length = null) {
          if ($length) {
              return mb_substr($string, $offset, $length);
          }
  
          return mb_substr($string, $offset);
      }
code_tokens: public static function extract ( $ string , $ offset , $ length = null ) { if ( $ length ) { return mb_substr ( $ string , $ offset , $ length ) ; } return mb_substr ( $ string , $ offset ) ; }
docstring: Extracts a portion of a string.
  
  @param string $string
  @param int $offset
  @param int $length
  @return string
docstring_tokens: Extracts a portion of a string .