in reply to About the use of the plural form for the name of variables
Good question -- to me it shows that you're taking some time to think about how the code will read, and that's excellent! Future developers will thank you.
My suggestion: write it so that when you read it back (in your head), it makes the most sense (keeping in mind that this language was written by a linguist). For me, that means you'd use @friends for your list.
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