pythoでコード自体は問題なく動くのにVS Codeがエラーを検知する

master_pw = ""
master_data = {"master_key":1234}
master_password = master_data["master_key"] 
while not master_pw == master_password:
    master_pw = str(input("Please enter master password: "))
    if str(master_password) == master_pw:
        print("You Have Successfully Logged In")
        exit()
    else: 
        i = 0 
        while i < 2: 
            print("The password is incorrect.")
            master_pw = str(input("Please enter master password"))
            i += 1
            print(i)
        else: 
            print("You have made mistakes 3 times. Quitting program... ")
            exit()

def greet
  puts Hello World
end