625.310 County, municipal, and district obligations.—An insurer may invest in bonds, notes, warrants, and other securities not in default of any county, district, incorporated city, or school district in any state of the United States, or the District of Columbia, or in any province of Canada, which are the direct obligations of such county, district, city, or school district and for payment of the principal and interest of which the county, district, city, or school district has lawful authority to levy taxes or make assessments.