All members of the Police Department shall, before entering upon duty as police officers, take and subscribe an oath of office substantially in the following form:
"I do solemnly swear that I will support the Constitution of the United States and of the State of Illinois, and that I will faithfully discharge the duties of the office of police officer of the Village of Oak Park to the best of my ability."
Such oath shall be subscribed and sworn to before some officer authorized by the laws of this State to administer oaths and the certificates thereof shall be filed in the office of the Village Clerk. (1981 Code)