Kellogg Co. argued that Cook County is obligated to provide free steam heat to its warehouse at 3249 S. Kedzie Ave. — based on a “covenant running with the land” in a 1973 agreement between the county and the city of Chicago — but the county countered by arguing this would violate the portion of the Illinois Constitution that says: “Public funds, property or credit shall be used only for public purposes.”Back in 1973, the city owned a municipal heating plant that supplied steam to …