Updates rotation and impulse direction

def update_rotation(self, dt, buttons):
        """
        Updates rotation and impulse direction
        """
        assert isinstance(buttons, dict)

        ma = buttons['right'] - buttons['left']
        if ma != 0:
            self.stats['battery'] -= self.battery_use['angular']
            self.rotation += ma * dt * self.angular_velocity

        # Redirect velocity in new direction
        a = math.radians(self.rotation)
        self.impulse_dir = eu.Vector2(math.sin(a), math.cos(a))