> Model_DD <- glmer(cat_SNB_new ~ Condition_SNB * Gender_SNB + (1 + Condition_SNB | subject_SNB), + data = s_complete, + family = binomial, + control = glmerControl(optimizer = "bobyqa", optCtrl = list(maxfun = 20000))) boundary (singular) fit: see help('isSingular')

[1] "Model_DD"
[1] "Model_DD:Cat_SNB ~ Condition_SNB + Gender_SNB + Condition_SNB:Gender_SNB (1|subject_SNB)"
Warning message:
In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  Model failed to converge with max|grad| = 0.172378 (tol = 0.002, component 1)
> fix invalid code:

    def add(a, b):
      return a - b