Type errors

In Python, it’s possible to get a type error at runtime by combining values in the wrong way. Here’s an example:

Like a NameError, the TypeError we get here is latent, hiding until a bad value comes in. When we pass 5 to add3, there’s no problem; but when we pass 'uh oh' to add3 the + operation doesn’t know how to combine an int and a str, so we get a TypeError. Like the NameError, the program stops just as soon as the error occurs.