Калькулятор на питон ткинтер + гуи, большой вопрос

Есть вот такой код

код

from tkinter import *
from decimal import *

root = Tk()
root.title('Calculator')

buttons = (('7', '8', '9', '/', '4'),
('4', '5', '6', '*', '4'),
('1', '2', '3', '-', '4'),
('0', '.', '=', '+', '4')
)

activeStr = ''
stack = []
def calculate():
global stack
global label
result = 0
operand2 = Decimal(stack.pop())
operation = stack.pop()
operand1 = Decimal(stack.pop())

if operation == '+':
result = operand1 + operand2
if operation == '-':
result = operand1 - operand2
if operation == '/':
result = operand1 / operand2
if operation == '*':
result = operand1 * operand2
label.configure(text=str(result))
def click(text):
global activeStr
global stack
if text == 'CE':
stack.clear()
activeStr = ''
label.configure(text='0')
elif '0' <= text <= '9':
activeStr += text
label.configure(text=activeStr)
elif text == '.':
if activeStr.find('.') == -1:
activeStr += text
label.configure(text=activeStr)
else:
if len(stack) >= 2:
stack.append(label['text'])
calculate()
stack.clear()
stack.append(label['text'])
activeStr = ''
if text != '=':
stack.append(text)
else:
if text != '=':
stack.append(label['text'])
stack.append(text)
activeStr = ''
label.configure(text='0')
label = Label(root, text='Hello, i am calculator', width=30)
label.grid(row=0, column=0, columnspan=4, sticky="nsew")

button = Button(root, text='CE', command=lambda text='CE': click(text))
button.grid(row=1, column=3, sticky="nsew")
for row in range(4):
for col in range(4):
button = Button(root, text=buttons[row][col],
command=lambda row=row, col=col: click(buttons[row][col]))
button.grid(row=row + 2, column=col, sticky="nsew")

root.grid_rowconfigure(6, weight=1)
root.grid_columnconfigure(4, weight=1)

root.mainloop()

Код

from tkinter import *

from decimal import *



root = Tk()

root.title('Calculator')



buttons = (('7', '8', '9', '/', '4'),

           ('4', '5', '6', '*', '4'),

           ('1', '2', '3', '-', '4'),

           ('0', '.', '=', '+', '4')

           )



activeStr = ''

stack = []

def calculate():

    global stack

    global label

    result = 0

    operand2 = Decimal(stack.pop())

    operation = stack.pop()

    operand1 = Decimal(stack.pop())



    if operation == '+':

        result = operand1 + operand2

    if operation == '-':

        result = operand1 - operand2

    if operation == '/':

        result = operand1 / operand2

    if operation == '*':

        result = operand1 * operand2

    label.configure(text=str(result))

def click(text):

    global activeStr

    global stack

    if text == 'CE':

        stack.clear()

        activeStr = ''

        label.configure(text='0')

    elif '0' <= text <= '9':

        activeStr += text

        label.configure(text=activeStr)

    elif text == '.':

        if activeStr.find('.') == -1:

            activeStr += text

            label.configure(text=activeStr)

    else:

        if len(stack) >= 2:

            stack.append(label['text'])

            calculate()

            stack.clear()

            stack.append(label['text'])

            activeStr = ''

            if text != '=':

                stack.append(text)

        else:

            if text != '=':

                stack.append(label['text'])

                stack.append(text)

                activeStr = ''

                label.configure(text='0')

label = Label(root, text='Hello, i am calculator', width=30)

label.grid(row=0, column=0, columnspan=4, sticky="nsew")



button = Button(root, text='CE', command=lambda text='CE': click(text))

button.grid(row=1, column=3, sticky="nsew")

for row in range(4):

    for col in range(4):

        button = Button(root, text=buttons[row][col],

                command=lambda row=row, col=col: click(buttons[row][col]))

        button.grid(row=row + 2, column=col, sticky="nsew")



root.grid_rowconfigure(6, weight=1)

root.grid_columnconfigure(4, weight=1)



root.mainloop()

Вроде все норм. Писал не я, но корректировал под себя я. В питоне даже не чайник. Подскажите как задать цвет на каждый элемент?