Agency is extinguished:
(1) By its revocation;
(2) By the withdrawal of the agent;
(3) By the death, civil interdiction, insanity or insolvency of the principal or of the agent;
(4) By the dissolution of the firm or corporation which entrusted or accepted the agency;
(5) By the accomplishment of the object or purpose of the agency;
(6) By the expiration of the period for which the agency was constituted. (1732a)