def f(gateType = 'AND', input = 'A'):
  (ab, delay) = {
    'AND': ({'A': (a,b), 'B': (c,d)}, delay1),
    'OR': ({'A': (x,y), 'B': (k,l)}, delay2),
    ('INV': {'A': (g,h)}, delay3)
  }[gateType]

  (a,b) = ab[input]