def pmt(self):
"""
Calculate the loan payment for the loan. Called from the __init__().
Args:
self.rate: periodic interest rate (i.e. interest rate / period)
self.periods*(self.term+1): total number of compounding periods
self.present_value: the loan amount
Returns:
self.payment: amount of each payment (float)
"""
self.payment = Amortizer.pmt(self.rate, self.periods*(self.term+1), self.present_value)
