code: func IsKnownSystemPriorityClass(pc *PriorityClass) (bool, error) {
  	for _, spc := range systemPriorityClasses {
  		if spc.Name == pc.Name {
  			if spc.Value != pc.Value {
  				return false, fmt.Errorf("value of %v PriorityClass must be %v", spc.Name, spc.Value)
  			}
  			if spc.GlobalDefault != pc.GlobalDefault {
  				return false, fmt.Errorf("globalDefault of %v PriorityClass must be %v", spc.Name, spc.GlobalDefault)
  			}
  			return true, nil
  		}
  	}
  	return false, fmt.Errorf("%v is not a known system priority class", pc.Name)
  }
docs: // IsKnownSystemPriorityClass checks that "pc" is equal to one of the system PriorityClasses.
  // It ignores "description", labels, annotations, etc. of the PriorityClass.