# Ensure arg is not valid

``

    assert_not  arg (anything)

Raises an exception if the argument is not either nil or false.

Introduced in v3.3

## Examples

# Example 1
``
    assert_not false
    assert_not nil
    assert_not 1 == 5
    assert true
| ``
    # Simple assertions
    # As false is either nil or false, this assertion passes
    # As nil is either nil or false, this assertion passes
    # These numbers are not equal
    # This will raise an exception
# Example 2
``
    assert_not true , "oops"
| ``
    # Communicating error messages
    # This will raise an exception containing the message "oops"