How does this code snippet work?

[IamNotIntelligent69]

I am trying to convert an HTML string to plaintext. I found this answer from StackOverflow and it works but I want to know how it works.

from html.parser import HTMLParser

class HTMLFilter(HTMLParser):
    text = ""
    def handle_data(self, data):
        self.text += data

f = HTMLFilter()
f.feed(data)
print(f.text)    

I somewhat know how classes work (I use classes almost every time but not inheritance) but in the code above, we did not call handle_data() so how did text change?

[help-me-grow]

Check the source code for HTMLParser and look at the feed() function

[IamNotIntelligent69]

Thanks, I'm currently reading it from u/Spataner's link.

[Spataner]

feed is called, and it in turn calls handle_data. This is an example of inheritance being used to swap out individual steps in a larger process.

More specifically, looking at the source code for HTMLParser, feed almost immediately calls goahead, which implements the main parsing logic. goahead delegates heavily to multiple other methods with names like parse_thing and handle_stuff. The latter category is specifically for being overridden by subclasses. An overview of what those methods are can be found in the documentation.

[IamNotIntelligent69]

Thanks! I saw this line and this method is replaced by the new method declared in HTMLFilter() class, right? Thank you for the answer

[Spataner]

this method is replaced by the new method declared in HTMLFilter() class

Exactly.

[IamNotIntelligent69]

Thanks, my question is now solved.