Python create save button that saves an edited version to the same file(not save as)

Here's a quick example of a save and save as function, with comments:

def save(self):    contents = self.textbox.get(1.0,"end-1c") #store the contents of the text widget in a str    try:                                       #this try/except block checks to        with open(self.f, 'w') as outputFile:  #see if the str containing the output            outputFile.write(contents)         #file (self.f) exists, and we can write to it,    except AttributeError:                     #and if it doesn't,        self.save_as()                         #call save_asdef save_as(self):    contents = self.textbox.get(1.0,"end-1c")    self.f = tkFileDialog.asksaveasfilename(   #this will make the file path a string        defaultextension=".z",                 #so it's easier to check if it exists        filetypes = (("ztext file", "*.z"),    #in the save function                     ("zytext", "*.zy")))    with open(self.f, 'w') as outputFile:        outputFile.write(contents)

There are other ways to do this, but this will work in a pinch. Just think about what the save function needs: text to save and a file to save in, and go from there.