why my function doesn't work

[ichabod801]

'tax' is the function itself, not the result of calling the function. What it is printing is not an error or warning, it is the repr of the function. To print the result, either print it directly (print(tax(2005, 100))), or store it in a variable and print the variable:

owed = tax(2005, 100)
print(owed)