Proof of commission of any act enumerated in this section is proof that the legislator committing the act has breached the legislator's public duty. A legislator may not:
(1) accept a fee, contingent fee, or any other compensation, except the official compensation provided by statute, for promoting or opposing the passage of legislation;
(2) seek other employment for the legislator or solicit a contract for the legislator's services by the use of the office;
(3) accept a fee or other compensation, except as provided for in 5-2-302, from a Montana state agency or a political subdivision of the state of Montana for speaking to the agency or political subdivision; or
(4) use the funds provided for in 5-2-204 for an activity that is prohibited.