assert to verify values

---

examples/modules/raise_exception.py

def add(x, y):
    return x * y

for x, y, z in [(2, 2, 4), (9, 2, 11), (2, 3, 5)]:
    print(f"add({x}, {y}) == {z}")
    if add(x, y) != z:
        raise Exception(f"add({x}, {y}) != {z}")
        #raise AssertionError

add(2, 2) == 4
add(9, 2) == 11
Traceback (most recent call last):
  File "examples/functions/raise_exception.py", line 7, in <module>
    raise Exception(f"add({x}, {y}) != {z}")
Exception: add(9, 2) != 11

examples/modules/assert.py

def add(x, y):
    return x * y

for x, y, z in [(2, 2, 4), (9, 2, 11), (2, 3, 5)]:
    print(f"add({x}, {y}) == {z}")
    assert add(x, y) == z

add(2, 2) == 4
add(9, 2) == 11
Traceback (most recent call last):
  File "examples/functions/assert.py", line 6, in <module>
    assert add(x, y) == z
AssertionError