Fix typo + wrong code

[remicres]

Related Issue(s): #

Description:

I have fixed a small typo and a wrong code snippet.
Indeed the 26th cell is

with open(item.self_href) as f:
    print(f.read())

But it should be the catalog object that is read.

PR Checklist:

• Code is formatted (run pre-commit run --all-files)
• Tests pass (run scripts/test)
• Documentation has been updated to reflect changes, if applicable
• This PR maintains or improves overall codebase code coverage.
• Changes are added to the CHANGELOG. See the docs for information about adding to the changelog.