static isValidKeySerialization(keySequence) {
    if (keySequence.length > 0) {
      return !!KeySequenceParser.parse(keySequence, { ensureValidKeys: true }).combination;
    } else {
      return false;
    }
  }
Whether the specified key sequence is valid (is of the correct format and contains
combinations consisting entirely of valid keys)
@param {KeySequenceString} keySequence Key sequence to validate
@returns {boolean} Whether the key sequence is valid