code: def _turn(self, speed, degrees, brake=True, block=True):
          
  
          # The distance each wheel needs to travel
          distance_mm = (abs(degrees) / 360) * self.circumference_mm
  
          # The number of rotations to move distance_mm
          rotations = distance_mm/self.wheel.circumference_mm
  
          log.debug("%s: turn() degrees %s, distance_mm %s, rotations %s, degrees %s" %
              (self, degrees, distance_mm, rotations, degrees))
  
          # If degrees is positive rotate clockwise
          if degrees > 0:
              MoveTank.on_for_rotations(self, speed, speed * -1, rotations, brake, block)
  
          # If degrees is negative rotate counter-clockwise
          else:
              rotations = distance_mm / self.wheel.circumference_mm
              MoveTank.on_for_rotations(self, speed * -1, speed, rotations, brake, block)
docs: Rotate in place 'degrees'. Both wheels must turn at the same speed for us
          to rotate in place.