It shall be the duty of the occupant of any premises within the city limits, or in case the same are unoccupied, then the owner or his agent, to keep the sidewalks in front of and adjoining his premises clean and safe for pedestrians, and to repair the same from time to time, and such occupant, owner, or agent shall, with all reasonable dispatch, remove snow, ice, slush, mud, or other impediments to safe and convenient foot travel. (1983 Code § 12.04.020)