Error in if (alpha[1] == "estimate") 1 else 20: argument is of length zero

[panastheod]

Hi,
I am trying to use your R package geneSLOPE and while using the test data all work fine with my dataset i get this error
when i run :
slope.result <- select_snps(clumping.result, fdr=0.1)
Error in if (alpha[1] == "estimate") 1 else 20 :
argument is of length zero
Do you know the source of this error?
Thanks in advance.