_historyTableForget(numberOfEntriesToForget = 1) {
        const shiftedAway = [];
        for (let i = 0; i < numberOfEntriesToForget; i++) {
            shiftedAway.push(this.historyTable.shift());
            // Update the history table index accordingly
            this.historyTableIndex--;
            if (this.historyTableIndex < 0) {
                // In case this function is called more times than there is states in the history table
                this.historyTableIndex = 0;
            }
        }

        if (shiftedAway.length === 1) {
            return shiftedAway[0];
        }

        return shiftedAway;
    }
Make the history table forget its first N elements, shifting its indexes in the process.
`N` being given as the `numberOfEntriesToForget` parameter.

@param {Number} numberOfEntriesToForget
@returns {object|Array<object>} The discarded objects, in an Array.
@private