Simple Calculator using class object composition

I have been doing class and object for a while , but still having some issues. Can somebody please look at my sample code and correct me? I will be greatly appreciated. Thank you.

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class Calculator:    

    def __init__(self):
       
        while True:
            print("Enter q or Q to quit")
            self.num = input("Enter number --> ")
            if self.num == "q" or self.num == "Q":
                break
            elif self.num.isalpha():
                print("You did not enter number!!!!")
                continue
            self.num_1 = input("Enter another number --> ")
            if self.num_1 == "q" or self.num_1 == "Q":
                break
            elif self.num_1.isalpha():
                print("You did not enter number!!!!")
                continue
            print('''
            1. add
            2. subtraction
            3. multiplication
            4. divide''')
            self.pick = input("Pick --> ")
        
            if self.pick == "1":
                self.addition()
            elif self.pick == "2":
                self.subtraction()
            elif self.pick == "3":
                self.multiplication()
            elif self.pick == "4":
                self.division()
            else:
                print("Your choice is not available")
                continue
            
    def addition(self):
        print(int(self.num) + int(self.num_1))
        
    def subtraction(self):
        print(int(self.num) - int(self.num_1))
        
    def multiplication(self):
        print(int(self.num) * int(self.num_1))
        
    def division(self):
        print(int(self.num) / int(self.num_1))
    
    
cal = Calculator()

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