code: public List<String> listDefinedBuses() {
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.entry(tc, "listDefinedBuses", this);
          }
  
          List buses = null;
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.exit(tc, "listDefinedBuses", buses);
          }
  
          return buses;
      }
docs: Returns a list of configured buses in this cell. For liberty this method
  will return the null value, because no directory structure is maintained
  in liberty for a bus.
  
  @return String[] list of buses in cell