int set_decryption_pid(MOBIData *m, const char *pid) {
    printf("\nVerifying PID %s...", pid);
    MOBI_RET mobi_ret = mobi_drm_setkey(m, pid);
    if (mobi_ret != MOBI_SUCCESS) {
        printf("failed (%s)\n", libmobi_msg(mobi_ret));
        return (int) mobi_ret;
    }
    printf("ok\n");
    return SUCCESS;
}
int set_decryption_pid(MOBIData *m, const char *pid) {
    printf("\nVerifying PID %s...", pid);
    MOBI_RET mobi_ret = mobi_drm_setkey(m, pid);
    if (mobi_ret != MOBI_SUCCESS) {
        printf("failed (%s)\n", libmobi_msg(mobi_ret));
        return (int) mobi_ret;
    }
    printf("ok\n");
    return SUCCESS;
}