code: public Collection<Effort> effortRecords(EffortFilter filter) {
          return get(Effort.class, (filter != null) ? filter : new EffortFilter());
      }
docs: Get effort records filtered by the criteria specified in the passed in
  filter.
  
  @param filter Limit the items returned. If null, then all items returned.
  @return Collection of items as specified in the filter.