>>> from discount4 import discount4

>>> round(discount4(90, 10, 1), 2)
99.0
>>> round(discount4(12, 21, 6), 2)
87.12
>>> round(discount4(80, 25, 1), 2)
100.0
>>> round(discount4(45, 21, 2), 2)
103.9
>>> round(discount4(23.2, 16, 7), 2)
180.38