original_string: public function toString($separator = null)
      {
          if (!is_null($separator)) {
              $this->_separator = $separator;
          }
  
          $this->_prepareData();
          return $this->__toString();
      }
code: public function toString($separator = null)
      {
          if (!is_null($separator)) {
              $this->_separator = $separator;
          }
  
          $this->_prepareData();
          return $this->__toString();
      }
code_tokens: public function toString ( $ separator = null ) { if ( ! is_null ( $ separator ) ) { $ this -> _separator = $ separator ; } $ this -> _prepareData ( ) ; return $ this -> __toString ( ) ; }
docstring: return object as string
  each data value separated by coma
  
  @param string $separator
  @return string
docstring_tokens: return object as string each data value separated by coma