No owner, lessee or other person in control of any grate, door or opening in any sidewalk in the city shall permit the same to remain open any longer than may be reasonably necessary to enable such owner, lessee or occupant to move or remove goods in the course of his trade or business; and while open, such grate, door or other opening shall be properly barricaded so as to prevent pedestrians from falling into the same.
('71 Code, § 549.08) Penalty, see § 101.99