code: public Collection<RegressionPlan> regressionPlans(RegressionPlanFilter filter) {
          return get(RegressionPlan.class, (filter != null) ? filter : new RegressionPlanFilter());
      }
docs: Gets regression plans filtered by the criteria specified in the passed in filter.
  
  @param filter Limit the items returned. If null, then all items are returned.
  @return Collection of items as specified in the filter.