File "<string>", line 19, in <module> error is related to what?

[deanhystad]

The thing that was missing was the second "i" in "__init__()". Your Portfolio class did not have an __init__() method because you made a mistake when typing the method name. Instead you wrote a __int__() method which was never used.

When you created a Portfolio object Python looked to see if the Portfolio class has an __init__() method. It did not because of your typing error. This resulted in the holdings dictionary never being created.

What is your question about this code?

for (ticker, shares) in p:
    print(ticker, shares)

If you fix the typing error in the Portfolio.__init__() method name the loop will work. If you don't fix the method name your program never reaches this point in the code because it crashes when you call Portfolio.buy().