Trouble understanding 'Making custom containers'

I am a noob , so when Mosh explained the topic ‘making custom containers’ I honestly can’t understand anything, especially the tag parts.

Can someone explain like i’m 5 and create another example with user friendly words and terms to make me understand how to learn to create custom containers please?

Thank you!

When Mosh refers to containers, he is referring to data structures i.e. lists, sets, or dictionaries. When he refers to custom containers, he means making your own type of data structure to fit a certain use case.

In his example, he is implementing a container that tracks tags. He is implementing methods similar to what you would see in a data structure.

If you familiarize yourself with python data structures, it may help you understand