'Rotate the list. The last client is moved to first position.
If maintain_index is True the current_index is adjusted,
such that the same client stays current and goes down in list.'

def rotate_down(self, maintain_index=True):

    if (len(self.clients) > 1):
        self.clients.insert(0, self.clients.pop())
        if maintain_index:
            self.current_index += 1
