How have courts treated civil service employees and a civil service system?

11 Rexstrew v. City of Huntington Park, supra (1942) 20 Cal.2d 630, 128 P.2d 23, likewise involved civil service employees and an apparently comparable civil service system.

12 The usual reasons for requiring a party interested in obtaining a certain result to produce and prove the facts requisite to that result similarly apply in the instant situation. Not all earnings would be deductible; for example, earnings from night or weekend work, which would not have been inconsistent with school employment, are not to be deducted. (Beseman v. Remy (1958) 160 Cal.App.2d 437, 445, 325 P.2d 578.) Hence the burden should rest upon the board to prove which particular earnings, if any, qualify for mitigation.