lib/workflow-in-memory-backend.js
function deleteWorkflow(workflow, meta, callback) {
            if (typeof (meta) === 'function') {
                callback = meta;
                meta = {};
            }

            if (workflows[workflow.uuid]) {
                return callback(null, (delete workflows[workflow.uuid]));
            } else {
                return callback(null, false);
            }
        }
function deleteWorkflow(workflow, meta, callback) {
            if (typeof (meta) === 'function') {
                callback = meta;
                meta = {};
            }

            if (workflows[workflow.uuid]) {
                return callback(null, (delete workflows[workflow.uuid]));
            } else {
                return callback(null, false);
            }
        }
workflow - the workflow object meta - Any additional information to pass to the backend which is not workflow properties callback - f(err, boolean)