code: function verifyRelativeDirection(direction) {
    if (!RELATIVE_DIRECTIONS.includes(direction)) {
      throw new Error(
        `Unknown direction: '${direction}'. Should be one of: '${FORWARD}', '${RIGHT}', '${BACKWARD}' or '${LEFT}'.`,
      );
    }
  }
docs: Checks if the given direction is a valid relative direction.
  
  @param {string} direction The direction.
  
  @throws Will throw if the direction is not valid.