Stack Implementation using Python

 Code is given below:

#Stack

class stack:

    def __init__(self):

        self.stack=[]

    def push(self,value):

        if value not in self.stack:

            self.stack.append(value)

        else:

            print("Data is already there in stack...")

    def pop(self):

        if self.stack is None:

            print("Stack is empty")

        else:

            self.stack.pop()

            print("Popped Successfully")

    def display(self):

        for i in range(len(self.stack)-1,-1,-1):

            print(self.stack[i])

            

obj=stack()

print("STACK OPERATIONS")

while True:

    print("\nPress\n1.PUSH\n2.POP\n3.DISPLAY\n4.EXIT")

    choice=int(input("Enter your choice : "))

    if choice==1:

        number=int(input("Enter the number : "))

        obj.push(number)

    elif choice==2:

        obj.pop()

    elif choice==3:

        obj.display()

    elif choice==4:

        break

    else:

        pass