demo_python_ref_keyword_assert_1.py:
​x
 
x = "hello"
​
#if condition returns True, then nothing happens:
assert x == "hello"
​
#if condition returns False, AssertionError is raised:
assert x == "goodbye"
​
C:\Users\My Name>python demo_python_ref_keyword_assert_1.py
Traceback (most recent call last):
  File "demo_python_ref_keyword_assert_1.py", line 5, in <module>
    assert x == "goodbye"
AssertionError