readCamera(source) {
    const cameras = [];
    if (typeof source === 'string') {
      const doc = parse(source);
      extend(cameras, this.readCameraFromDocument(doc));
    } else if (isDocument(source)) {
      extend(
        cameras,
        this.readCameraFromDocument(/** @type {Document} */ (source)),
      );
    } else {
      extend(cameras, this.readCameraFromNode(/** @type {Element} */ (source)));
    }
    return cameras;
  }
Read the cameras of the KML.

@param {Document|Element|string} source Source.
@return {Array<KMLCamera>} Cameras.
@api