Why MagicFilter in aiogram doesn't have "__contains__", but have "in_"?

[aminabbasov]

In my opinion, having the option to check the presence of F or MagicFilter with built-in Python syntax will be much better than the current in_ method.

My view:

F.content_type in {ContentType.PHOTO, ContentType.VIDEO}

Current:

F.content_type.in_({ContentType.PHOTO, ContentType.VIDEO})

But I think this is quite an obvious idea to implement __contains__ and check element existence in a collection, so I guess that there is a reason for not doing that. And I want to know it, if so =)

[JrooTJunior]

Because in operator calls __contains__ on the right operand inplace and returns always boolean value and the magic filter, on the contrary, works in a delayed manner when necessary (on imcoming events).

So when you execute the following:

F.content_type in {ContentType.PHOTO, ContentType.VIDEO}

The presence of the filter object (F.content_type == delayed getattr) in the sequence shown on the right will be checked immediately.

and when you execute

F.content_type.in_({ContentType.PHOTO, ContentType.VIDEO})

the contains operation will be added to the filter and when resolve method the presence of the value of the specified attribute will be checked.

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The same as in the SQLAlchemy ColumnClause.in_ operator

[aminabbasov]

Thanks for the answer! And by chance, I want to express my gratitude for aiogram! I remember trying python-telegram-bot before discovering it, and I found it rather inconvenient. However, using aiogram has been a much more pleasant and easier experience. Thank you! :)