语法错误每月付款计算器

Question

此程序用于计算贷款的每月还款额。我不断收到该语句的无效语法错误：返回monthly_payment。我计算出一个错误。此外，利率在计算和格式化结果时都应只保留小数点后一位。

  enter code here#!/usr/bin/env python3
#
# Monthly Payment Calculator
#

from decimal import Decimal
import locale as lc

def get_month_payment(Loan_amount,Yearly_interest_rate,Years):
    monthly_interest_rate = Yearly_interest_rate/12/100
    months = Years*12
    monthly_payment = Decimal("0.00")
    for i in range(months):
        monthly_payment += Loan_amount
        month_payment = Loan_amount*monthly_interst_rate/ (1-1/(
            1 + monthly_interesr_rate)**months)
        monthly_payment +=  month_payment
        monthly_payment =  monthly_payment.quantize(Decimal("1.00") 
    return monthly_payment                                            



def main():
    print("Monthly Payment Calculator")
    print()
    print ("DATA ENTRY")
    choice = "y"
    while choice.lower() == "y":

       principle = Decimal(input("Loan amount: "))
       annual_interest_rate = Decimal(input("Yearly interest rate: "))
       duration=int(input("Years: "))
       month_payment = get_month_payment(
           Loan_amount,Yearly_interest_rate,Years)

       print()


       result = lc.setlocale(lc.LC_ALL, "")
       if result == "C":

           lc.setlocale(lc.LC_ALL, "en_US")
           line = "{:16} {:>16}"
           print(line.format("Loan amount:",
            lc.currency(Loan_amount, grouping=True)))
           print(line.format("Yearly interest rate:",
                             str(interest_rate) + "%"))
           print(line.format("Month payment:",
                   lc.currency(monthly_payment, grouping=True)), "\n")

           choice = input("Continue? (y/n): ")
           print()

           print("Good Bye!")

if __name__ == "__main__":
    main()