$message_entity->head->add("Reply-To", $CONFIG{'reply-to'}) if defined $CONFIG{'reply-to'};
$message_entity->head->add("Bcc", $CONFIG{'bcc'}) if defined $CONFIG{'bcc'};
$message_entity->head->add("User-Agent", $USER_AGENT);
$message_entity->head->add("Reply-To", $CONFIG{'reply-to'}) if defined $CONFIG{'reply-to'};
$message_entity->head->add("Bcc", $CONFIG{'bcc'}) if defined $CONFIG{'bcc'};
$message_entity->head->add("User-Agent", $USER_AGENT);