The descriptions of lands in an improvement district in any incorporated town or city of the first or second class which are based upon a plat, of a part or the whole, of the municipality, which has been filed in the office of the municipal clerk and is not in conflict with a duly executed and recorded plat of the same territory in the office of the circuit clerk and ex officio recorder of the county shall be valid descriptions of the lands so platted for the purpose of making the assessment of benefits for any local improvement district on the lands within the territory so platted and for the collection of the assessments of benefits on the lands so platted and described, including suits brought to enforce their collection.