3 – Type unions with the vertical bar in isinstance

The vertical bar | can be used to combine types (to create type unions) since Python 3.10. This lets you create type unions in a very ergonomic way.

You can use it, for example, inside isinstance checks. This lets you check if a value belongs to one of two or more types, like so:

isinstance(x, typ1 | typ2 | ...)

This is definitely nicer than

isinstance(x, typ1) or isinstance(x, typ2) or ...

And it is also nicer than the traditional alternative with a tuple of types:

isinstance(x, (typ1, typ2, ...))

Here is a complete example:

def is_number(x):
    return isinstance(x, int | float | complex)

print(is_number(42))  # True
print(is_number("hey"))  # False