original_string: public function setMessageId($id = true)
      {
          if ($id === null || $id === false) {
              return $this;
          } elseif ($id === true) {
              $id = $this->createMessageId();
          }
  
          if ($this->_messageId === null) {
              $id = $this->_filterOther($id);
              $this->_messageId = $id;
              $this->_storeHeader('Message-Id', '<' . $this->_messageId . '>');
          } else {
              /**
               * @see Zend_Mail_Exception
               */
              // require_once 'Zend/Mail/Exception.php';
              throw new Zend_Mail_Exception('Message-ID set twice');
          }
  
          return $this;
      }
code: public function setMessageId($id = true)
      {
          if ($id === null || $id === false) {
              return $this;
          } elseif ($id === true) {
              $id = $this->createMessageId();
          }
  
          if ($this->_messageId === null) {
              $id = $this->_filterOther($id);
              $this->_messageId = $id;
              $this->_storeHeader('Message-Id', '<' . $this->_messageId . '>');
          } else {
              /**
               * @see Zend_Mail_Exception
               */
              // require_once 'Zend/Mail/Exception.php';
              throw new Zend_Mail_Exception('Message-ID set twice');
          }
  
          return $this;
      }
code_tokens: public function setMessageId ( $ id = true ) { if ( $ id === null || $ id === false ) { return $ this ; } elseif ( $ id === true ) { $ id = $ this -> createMessageId ( ) ; } if ( $ this -> _messageId === null ) { $ id = $ this -> _filterOther ( $ id ) ; $ this -> _messageId = $ id ; $ this -> _storeHeader ( 'Message-Id' , '<' . $ this -> _messageId . '>' ) ; } else { /**
               * @see Zend_Mail_Exception
               */ // require_once 'Zend/Mail/Exception.php'; throw new Zend_Mail_Exception ( 'Message-ID set twice' ) ; } return $ this ; }
docstring: Sets the Message-ID of the message
  
  @param   boolean|string  $id
  true  :Auto
  false :No set
  null  :No set
  string:Sets given string (Angle brackets is not necessary)
  @return  Zend_Mail Provides fluent interface
  @throws  Zend_Mail_Exception
docstring_tokens: Sets the Message - ID of the message