lib/parse/walkSummary.js
function walkSummary(summary, fn) {
    var parts = summary.getParts();

    return Promise.forEach(parts, function(part) {
        return walkArticles(part.getArticles(), fn);
    });
}
function walkSummary(summary, fn) {
    var parts = summary.getParts();

    return Promise.forEach(parts, function(part) {
        return walkArticles(part.getArticles(), fn);
    });
}
function walkSummary ( summary , fn ) { var parts = summary . getParts ( ) ; return Promise . forEach ( parts , function ( part ) { return walkArticles ( part . getArticles ( ) , fn ) ; } ) ; }
Walk over summary and execute "fn" on each article

@param {Summary} summary
@param {Function(article)}
@return {Promise}
Walk over summary and execute fn on each article