remove single tick line

I want to remove a single tick line (namely the first, on the spine's edge) but keep its label. I remember something like that: ax.get_xticklines()[0].set_markersize(0)

worked earlier, now not. In general, I can remove all or nothing.

Also,

for line in ax.get_xticklines():
   line.set_markersize(0)

removes all ticks, but:

k = 0
for line in ax.get_xticklines():
    if k ==0:    
       line.set_markersize(0)
       k+=1

ignores condition and keeps all ticks, no error or warning. matplotlib version 3.5.3