Return (f,arg) as previously registered with setErrorHandler
           or (None,None).

def GetErrorHandler(self):
        """Return (f,arg) as previously registered with setErrorHandler
           or (None,None)."""
        f,arg = libxml2mod.xmlTextReaderGetErrorHandler(self._o)
        if f is None:
            return None,None
        else:
            # assert f is _xmlTextReaderErrorFunc
            return arg