Need a detailed explanation of the below added line into documentation

[imrankuruvitta]

consider this line "A class in an [except] clause is compatible with an exception if it is the same class or a base class thereof (but not the other way around — an except clause listing a derived class is not compatible with a base class)" which comes under errors and exception in python tutorial web page, please give clear explanation, because as it is not understandable by programmers who is new to python , added screenshot below

Linked PRs

• gh-117597: Clarify exception handling in the tutorial #117681
• [3.12] gh-117597: Clarify exception handling in the tutorial (GH-117681) #117700

[nineteendo]

An except clause catches all errors of the specified class and its derived classes:

class ErrorA(Exception):
    pass

class ErrorAPlus(ErrorA):
    pass

class ErrorB(Exception):
    pass

for cls in [ErrorA, ErrorAPlus, ErrorB]:
    try:
        raise cls()
    except ErrorA:
        print("Caught error A")

Output:

Caught error A
Caught error A
Traceback (most recent call last):
  File "c:\Users\wanne\Desktop\test.py", line 12, in <module>
    raise cls()
ErrorB

Do you think the docs need to be updated with this?

[imrankuruvitta]

Yes, correct

[erlend-aasland]

Resolved by:

• gh-117597: Clarify exception handling in the tutorial #117681
• [3.12] gh-117597: Clarify exception handling in the tutorial (GH-117681) #117700 (auto-merge enabled)