processCollection = function (collection, callback) {
        if (util.isV1Collection(collection)) {
            // @todo: route this via print module to respect silent flags
            console.warn('newman: Newman v4 deprecates support for the v1 collection format');
            console.warn('  Use the Postman Native app to export collections in the v2 format\n');

            return transformer.convert(collection, COLLECTION_TRANSFORMER_OPTION, callback);
        }

        callback(null, collection);
    }
A helper method to process a collection and convert it to a V2 equivalent if necessary, and return it.

@todo Drop support for the v1 collection format in Newman v7?
Reference: https://github.com/postmanlabs/newman/pull/1660

@param {Object} collection The input collection, specified as a JSON object.
@param {Function} callback A handler function that consumes an error object and the processed collection.
@returns {*}