class Portfolio:
  def __init__(self, accounts, savings):
    self.accounts = accounts
    self.savings  = savings

  def total(self):
    total = 0
    for acct in self.accounts:
      total += acct.value()
    return total

  def apply_expenses(self, expense):
    for acct in self.accounts:
      expense = acct.apply_expenses(expense)

  def apply_savings(self, period):
    for acct, savings in zip(self.accounts, self.savings):
      acct.apply_savings(savings.current_value(period))

  def apply_return(self):
      for acct in self.accounts:
        acct.apply_return()

  def taxable_income(self):
    taxable = 0
    for acct in self.accounts:
      taxable += acct.get_capital_income() # Eventually split into capital and ordinary income.
    return taxable