code: private Severity getEffectiveSeverity(SeverityRule rule, Severity parentSeverity, Severity requestedSeverity) {
          Severity effectiveSeverity = requestedSeverity != null ? requestedSeverity : parentSeverity;
          return effectiveSeverity != null ? effectiveSeverity : rule.getSeverity();
      }
docs: Determines the effective severity for a rule to be executed.
  
  @param rule
  The rule.
  @param parentSeverity
  The severity inherited from the parent group.
  @param requestedSeverity
  The severity as specified on the rule in the parent group.
  @return The effective severity.