Q: "TypeError: 'str' object is not callable" when extracting from list I'm receiving this TypeError:
if 'Stack 6' in placement():
TypeError: 'str' object is not callable. 

Converting it to an integer in my for-each statement doesn't work, and I can't change any of the values in the list.
I cannot work out why this returns the TypeError:
game = [['Stack 6', 'Suit D', 9, 6],
  ['Stack 4', 'Suit B', 5, 0]]

for instructions in game:
    for placement in instructions:
        if 'Stack 6' in placement():
            print(placement)

Yet, this similar piece of code doesn't return any error:
elements = [['he', 'ne', 'Ar', 'Kr'],
    ['F', 'Cl', 'Br', 'I']]

for family in elements:
    for symbol in family:
        if 'a' in symbol.lower():
            print(symbol)


A: placement is not a function. It is a string. Putting parentheses after an object tells python to call that object, which it cannot do for a string. Remove the parentheses to fix the code.
The code with symbol.lower() works because lower() is a function which can be called in order to return something.
Here's a handy link to explain in more detail what callables are in python.
