docs: function set(appName, limits, callback) {
      if (!isObject(limits)) {
        return callback(new Error('To set a variable pass an object'));
      }
  
      var keyValues = {};
  
      if (limits.hasOwnProperty('memory')) {
        keyValues.memory = limits.memory;
      }
  
      if (limits.hasOwnProperty('cpu')) {
        keyValues.cpu = limits.cpu;
      }
  
      if (Object.keys(keyValues).length === 0) {
        return callback(new Error('Only cpu and memory limits are valid'));
      }
  
      commons.post(format('/%s/apps/%s/config/', deis.version, appName), keyValues,
          function onSetResponse(err, result) {
            callback(err, result ? extractLimits(result) : null);
          });
    }