get( keys ) {

		let map = this.weakMap;

		for ( let i = 0; i < keys.length - 1; i ++ ) {

			map = map.get( keys[ i ] );

			if ( map === undefined ) return undefined;

		}

		return map.get( keys[ keys.length - 1 ] );

	}
Returns the value for the given array of keys.

@param {Array<Object>} keys - List of keys.
@return {any} The value. Returns `undefined` if no value was found.