_iterateKeys(transform = (key) => key) {
        if (typeof this.keys === "undefined") {
            this.keys = [];
            if (commands$2.exists(this.name)) {
                const keyIndexes = commands$2.getKeyIndexes(this.name, this.args);
                for (const index of keyIndexes) {
                    this.args[index] = transform(this.args[index]);
                    this.keys.push(this.args[index]);
                }
            }
        }
        return this.keys;
    }
Iterate through the command arguments that are considered keys.

@param {Function} [transform=(key) => key] The transformation that should be applied to
each key. The transformations will persist.
@returns {string[]} The keys of the command.
@memberof Command