marginal_tax_calculator.py

def marginal_tax_calculator(brackets):
    def calculate(amount):
        if amount <= 0: return 0

        tax = floor = 0
        ceil = rate = None
        for bracket in brackets:
            if len(bracket) == 1:
                ceil = float('inf')
                rate = bracket[0]
            if len(bracket) == 2:
                ceil, rate = bracket

            if (amount > floor) and (amount <= ceil):
                tax += ((amount - floor) * rate)
            elif (amount > ceil):
                tax += ((ceil - floor) * rate)
            floor = ceil

        return tax
    return calculate

ontario_ltt = marginal_tax_calculator([
  [55000, 0.005],
  [250000, 0.01],
  [400000, 0.015],
  [2000000, 0.02],
  [0.025]
])