2 letter plate combinations

alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
def generatePlates(length):
  for i in range(1, 2**length-1):
    s = bin(i)[2:].zfill(length)
    for let_1 in alphabet:
      for let_2 in alphabet:
        if let_1 != let_2:
          yield s.replace('0',let_1).replace('1',let_2)

length4 = generatePlates(4)
length5 = generatePlates(5)
length6 = generatePlates(6)
#print(*length4)
#print(*length5)
#print(*length6)