    **/
    bool is_key() const {
      return _is_keyESC || _is_keyF1 || _is_keyF2 || _is_keyF3 ||
        _is_keyF4 || _is_keyF5 || _is_keyF6 || _is_keyF7 ||
        _is_keyF8 || _is_keyF9 || _is_keyF10 || _is_keyF11 ||
        _is_keyF12 || _is_keyPAUSE || _is_key1 || _is_key2 ||
        _is_key3 || _is_key4 || _is_key5 || _is_key6 ||
        _is_key7 || _is_key8 || _is_key9 || _is_key0 ||
        _is_keyBACKSPACE || _is_keyINSERT || _is_keyHOME ||
        _is_keyPAGEUP || _is_keyTAB || _is_keyQ || _is_keyW ||
        _is_keyE || _is_keyR || _is_keyT || _is_keyY ||
        _is_keyU || _is_keyI || _is_keyO || _is_keyP ||
        _is_keyDELETE || _is_keyEND || _is_keyPAGEDOWN ||
        _is_keyCAPSLOCK || _is_keyA || _is_keyS || _is_keyD ||
        _is_keyF || _is_keyG || _is_keyH || _is_keyJ ||
        _is_keyK || _is_keyL || _is_keyENTER ||
        _is_keySHIFTLEFT || _is_keyZ || _is_keyX || _is_keyC ||
        _is_keyV || _is_keyB || _is_keyN || _is_keyM ||
        _is_keySHIFTRIGHT || _is_keyARROWUP || _is_keyCTRLLEFT ||
        _is_keyAPPLEFT || _is_keyALT || _is_keySPACE || _is_keyALTGR ||
        _is_keyAPPRIGHT || _is_keyMENU || _is_keyCTRLRIGHT ||
        _is_keyARROWLEFT || _is_keyARROWDOWN || _is_keyARROWRIGHT ||
        _is_keyPAD0 || _is_keyPAD1 || _is_keyPAD2 ||
        _is_keyPAD3 || _is_keyPAD4 || _is_keyPAD5 ||
        _is_keyPAD6 || _is_keyPAD7 || _is_keyPAD8 ||
        _is_keyPAD9 || _is_keyPADADD || _is_keyPADSUB ||
        _is_keyPADMUL || _is_keyPADDIV;
Unknown