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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def step(self, amt=1):
        "Make a frame of the animation"
        self.move_particles()
        if self.has_moving_emitters:
            self.move_emitters()
        self.start_new_particles()
        self.render_particles()
        if self.emitters == [] and self.particles == []:
            self.completed = True