Beautiful Soup - Delete All HTML - Except Specific Classes

[dj99]

Hi all,

I have been looking everyhwere for this concept.

I wanted to delete all html except for the classes. I have listed
The idea is below. The code is not correct

html = '''\
<h2 class="1">section1</h2>
<p class="2">article1</p>
<p>article2</p>
<p class="3">article3</p>
<h1> Lorem Ipsum</h1>
<p> 3 Lorem ipsum dolor </p>",'lxml')
'''

soup = BeautifulSoup(html, 'lxml')


for tag in soup():
   if not class in ["1", "2"]:
        tag.decompose()
print(soup)

I cant find any code samples to show me this idea

Basically delete all html except for those classes listed in the list

Result:
Everything Deleted except:
<h2 class="1">section1</h2>
<p class="2">article1</p>
<p class="3">article3</p>

please do advise thank you