code: public void removeCohort(Cohort cohort, String studyId) {
          // Sanity check
          if (cohort == null) {
              logger.error("Cohort is null.");
              return;
          }
          removeCohort(cohort.getId(), studyId);
      }
docs: Remove a cohort of a given variant study metadata (from study ID).
  
  @param cohort     Cohort
  @param studyId  Study ID