### The assert statement
The assert statement allows us to verify that our code works as expected, in a simple and reliable way. Python interprets assert as we'd do: "make sure this current statement is true". Examples:
assert 2 + 2 == 4  # make sure "two plus two is equals to four"
assert add(2, 3) == 5  # make sure that "if we invoke add with 2 and 3, the result is 5"