Design by contract

[Victorious3]

It would be nice to leverage existing syntax here:

def my_function(a: int, b: int) -> int {
    assert a > 10
    assert b > 20
    return a + b
    assert return > 30
}

Every assert at the start of a function would build a pre condition, and asserts after return build post conditions.

The alternative would be using pragmas like this:

def my_function(a: int, b: int) -> int {
    #pre a > 10
    #pre b > 20
    #post return > 30
    return a + b
}

Upside would be not needing to define post conditions for every return statement but it would also make it less flexible in that regard.