josepheus problem - delete every 3rd element until the list goes empty

skip_every_3rd_element.py

a = ['1','2','3','4','5','6','7','8','9']

def josepheus(int_list, skip):
  skip = skip - 1 #list starts with 0 index
  idx = 0
  output = []
  while len(int_list)>0:
    idx = (skip+idx)%len(int_list)
    k = int_list.pop(idx)
    output.append(k)
  return output

assert josepheus(a,3)==['3','6','9','4','8','5','2','7','1']