When a petition signed by not less than ten citizens owning real estate in a precinct or ward in a city of the second or third class or by not less than twenty-five citizens owning real estate in a precinct or ward of a city of the first class, praying for the construction of a sidewalk or sidewalks in such precinct or ward is filed with the city clerk, the governing body may, in its discretion, by resolution, order such sidewalk or sidewalks constructed.