Newbie question: Strange TypeError

[Tim Isakson]

Howdy,

I'm a new python programmer - new to python, not so much to programming - 
my background was mainly C, with some C++, but it's rusty.  

I'm learning python to try and get back into some coding,
and am running into a problem - I'm writing a calculator in python and
wxPython as an exercise to learn both, and the following problem is
leaving me baffled.

I have an event handler, and it's getting called fine - but within the
event handler, I'm calling a class method, HandleInput.  The definition
and call are shown below:

    def HandleInput(self, input):
        if self.results.GetValue() == "0":
            return input
        elif newVal == True:
            return input
        else:
            tmpVal = self.results.GetValue() + input
            return tmpVal

    def OnButton1(self,e):
        tmpVal = self.HandleInput(self, "1")
        self.results.SetValue(tmpVal)

The call to HandleInput is made, but I get the following error:

Calling HandleInput(self, '1')
Traceback (most recent call last):
  File "pycalc.py", line 115, in OnButton1
    tmpVal = self.HandleInput(self, "1")
TypeError: HandleInput() takes exactly 2 arguments (3 given)

So far as I can tell, the offending call *IS* calling HandleInput with 2
arguments, but the interpreter obviously thinks different, and I'm at a
loss as to why that might be.

I'm sure I'm doing something odd and not noticing, and I'd appreciate any
help you can provide!

Thanks in advance,

Tim