EMI calculator

from tkinter import *

class EmiCalculator:

    def __init__(self):

        window = Tk() 

        window.title("Loan Calculator") 

        Label(window, text = "Annual Interest Rate").grid(row = 1,

                                        column = 1, sticky = W)

        Label(window, text = "Number of Years").grid(row = 2,

                                    column = 1, sticky = W)

        Label(window, text = "Loan Amount").grid(row = 3,

                                column = 1, sticky = W)

        Label(window, text = "Monthly Payment").grid(row = 4,

                                    column = 1, sticky = W)

        Label(window, text = "Total Payment").grid(row = 5,

                                    column = 1, sticky = W)

        self.annualInterestRateVar = StringVar()

        Entry(window, textvariable = self.annualInterestRateVar,

                    justify = RIGHT).grid(row = 1, column = 2)

        self.numberOfYearsVar = StringVar()

        Entry(window, textvariable = self.numberOfYearsVar,

                justify = RIGHT).grid(row = 2, column = 2)

        self.loanAmountVar = StringVar()

        Entry(window, textvariable = self.loanAmountVar,

            justify = RIGHT).grid(row = 3, column = 2)

        self.monthlyPaymentVar = StringVar()

        lblMonthlyPayment = Label(window, textvariable =

                        self.monthlyPaymentVar).grid(row = 4,

                        column = 2, sticky = E)

        self.totalPaymentVar = StringVar()

        lblTotalPayment = Label(window, textvariable =

                    self.totalPaymentVar).grid(row = 5,

                    column = 2, sticky = E)

        btComputePayment = Button(window, text = "Compute Payment",

                                command = self.computePayment).grid(

                                row = 6, column = 2, sticky = E)

        window.mainloop() 

    def computePayment(self):

        monthlyPayment = self.getMonthlyPayment(

        float(self.loanAmountVar.get()),

        float(self.annualInterestRateVar.get()) / 1200,

        int(self.numberOfYearsVar.get()))

        self.monthlyPaymentVar.set(format(monthlyPayment, '10.2f'))

        totalPayment = float(self.monthlyPaymentVar.get()) * 12 \

                                * int(self.numberOfYearsVar.get())

        self.totalPaymentVar.set(format(totalPayment, '10.2f'))

    def getMonthlyPayment(self, loanAmount, monthlyInterestRate, numberOfYears):

        monthlyPayment = loanAmount * monthlyInterestRate / (1

        - 1 / (1 + monthlyInterestRate) ** (numberOfYears * 12))

        return monthlyPayment;

        root = Tk() 

EmiCalculator()