Duplicate.

Clojure: it's unfinished and should be revoked/removed.

Tests require result to have a specific ordering but it's not mentioned anywhere. Either it should be specified, or the test should sort the user result before comparison, or the function should return a set instead.

@pbx,

Instead of just showing it in the description (and then forcing everyone to write their own), it might be a good idea to add the digits dictionary to Preloaded since every solution has the same dictionary. That way people could choose whether to use a preloaded dict of digit/letter pairs or to write their own (I'm guessing many people would use the preloaded dict).

LETTERS = {
    '2': 'ABC',
    '3': 'DEF',
    '4': 'GHI',
    '5': 'JKL',
    '6': 'MNO',
    '7': 'PQRS',
    '8': 'TUV',
    '9': 'WXYZ'
}

If you do add that to Preloaded, just make sure to tell people about the name of it in the description too. You could use separate markdown code sections for each language (so the Python dict only shows up in the description for Python not Clojure and vice versa).

Thanks!