"TypeError: CreateText() takes exactly 8 arguments (5 given)" with default arguments

def CreateText(win, text, x, y, size, font, color, style):
     txtObject = Text(Point(x,y), text)
     if size==None:
         txtObject.setSize(12)
     else:
         txtObject.setSize(size)
 
     if font==None:
         txtObject.setFace("courier")
     else:
         txtObject.setFace(font)
 
     if color==None:
         txtObject.setTextColor("black")
     else:
         txtObject.setTextColor(color)
 
     if style==None:
         txtObject.setStyle("normal")
     else:
         txtObject.setStyle(style)
 
     return txtObject
 
 def FlashingIntro(win, numTimes):
     txtIntro = CreateText(win, "CELSIUS CONVERTER!", 5,5,28)
     for i in range(numTimes):
         txtIntro.draw(win)
         sleep(.5)
         txtIntro.undraw()
         sleep(.5)
 

I'm trying to get the CreateText function to create a text object with my "default" values if the parameters are not used. (I've tried it with blank strings "" instead of None and no luck) I'm fairly new to Python and have little programming knowledge.

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