Adding alarm function to a Tkinter clock program

I need to create a function that allows setting alarms upon clicking on submenus in a menubar that I created inside the main window. This function is in a separate pop-up window(filewindow). The submenus have commands that points to the said function which also has an Entry widget in it for setting alarm time. Also I wanted to filter out the entries to be just integers. I guess Time Module should be imported to use strftime.