forceFromPublic(publicPath = null) {
        publicPath = publicPath || this.mix.config.publicPath;

        if (!this.relativePath().startsWith(publicPath)) {
            return new File(path.join(publicPath, this.relativePath()));
        }

        return this;
    }
Force the file's relative path to begin from the public path.

@param {string|null} [publicPath]