code: function tryParse(filePath: string, platforms: Set<string>): ?AssetPath {
    const result = parsePlatformFilePath(filePath, platforms);
    const {dirPath, baseName, platform, extension} = result;
    if (extension == null) {
      return null;
    }
    const {rootName, resolution} = parseBaseName(baseName);
    return {
      assetName: path.join(dirPath, `${rootName}.${extension}`),
      name: rootName,
      platform,
      resolution,
      type: extension,
    };
  }
docs: Return `null` if the `filePath` doesn't have a valid extension, required
  to describe the type of an asset.