Creating Python button saves edited file

If you want a save function that silently overwrites the current file, the basic thing to do is save a reference to the file name/location that the user chose, and then the next time you save you can reuse it instead of asking for a new one. The following (taken from a program of mine) has a "plain" save function that checks if there's a save file name on record, and either uses it (if it exists) or goes to the "save as" function. The plain version happens to have a return value so that it can interact with a load (open) function elsewhere in the program (asks the user whether to save unsaved work before loading a new file).

def save_plain(self, *args):    """    A plain save function. If there's no preexisting file name,    uses save_as() instead.    Parameter:        *args: may include an event    """    if self.savename: # if there's a name        self.save(self.savename) # then use it    elif self.save_as(): # else, use save_as instead        return True # successful save returns True    return False # else, return Falsedef save_as(self, *args):    """    A save as function, which asks for a name and only retains it if it was given    (canceling makes empty string, which isn't saved).    Parameter:        *args: may include an event    """    temp = filedialog.asksaveasfilename(defaultextension=".txt", \    filetypes=(('Text files', '.txt'),('All files', '.*'))) # ask for a name    if temp: # if we got one,        self.savename = temp # retain it        self.save(temp) # and pass it to save()        return True    return Falsedef save(self, filename):    """    Does the actual saving business of writing a file with the given name.    Parameter:        filename (string): the name of the file to write    """    try: # write the movelist to a file with the specified name        with open(filename, 'w', encoding = 'utf-8-sig') as output:            for item in self.movelist:                output.write(item + "\n")        self.unsaved_changes = False # they just saved, so there are no unsaved changes    except: # if that doesn't work for some reason, say so        messagebox.showerror(title="Error", \        message="Error saving file. Ensure that there is room and you have write permission.")