A policy may contain additional provisions not inconsistent with this code and which are: (1) Required to be inserted by the laws of the insurer's domicile; or (2) Necessary, on account of the manner in which the insurer is constituted or operated, in order to state the rights and obligations of the parties to the contract; or (3) Desired by the insurer and neither prohibited by law nor in conflict with any provisions required to be included therein.