'T.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.'

def index(self, value, start=None, stop=None):

    if ((start is None) and (stop is None)):
        return self.args.index(value)
    elif (stop is None):
        return self.args.index(value, start)
    else:
        return self.args.index(value, start, stop)
