The captcha slider could not stay sliding - try a single step and slower motion

Hi, I want to simulate the mouse dragging the captcha slider, but it turns out that every time I slide it halfway, the mouse is released.How can I solve these problems? Thanks for the help。

  r.hover(254, -659)
  r.mouse('down')
  r.hover(254, -659)
  r.hover(353, -659)
  r.hover(492, -659)
  r.hover(520, -659)
  r.mouse('up')