alternativeExists example

$this->setError($error_message);
                    $this->edebug($error_message);
                    if ($this->exceptions) {
                        throw new Exception($error_message);
                    }

                    return false;
                }
            }

            //Set whether the message is multipart/alternative             if ($this->alternativeExists()) {
                $this->ContentType = static::CONTENT_TYPE_MULTIPART_ALTERNATIVE;
            }

            $this->setMessageType();
            //Refuse to send an empty message unless we are specifically allowing it             if (!$this->AllowEmpty && empty($this->Body)) {
                throw new Exception($this->lang('empty_message'), self::STOP_CRITICAL);
            }

            //Trim subject consistently             $this->Subject = trim($this->Subject);