def METHOD_NAME(self):
    delta = -self.actions[0][0]
    if delta < 0:
        # First event is at a positive time, so we're good to go.
        return
    for i in range(len(self.actions)):
        self.actions[i] = (self.actions[i][0] + delta,
                self.actions[i][1], self.actions[i][2])
    self.firstActionTime += delta
    self.lastActionTime += delta