code: def start_circle_left(self, radius_m, velocity=VELOCITY):
          
          circumference = 2 * radius_m * math.pi
          rate = 360.0 * velocity / circumference
  
          self._set_vel_setpoint(velocity, 0.0, 0.0, -rate)
docs: Start a circular motion to the left. This function returns immediately.
  
          :param radius_m: The radius of the circle (meters)
          :param velocity: The velocity of the motion (meters/second)
          :return: