>> h = Hash.new({})
=> {}
>> h[:a][:b] = 1
=> 1
>> h
=> {}
>> h[:a]
=> {:b=>1}
>> h.keys
=> []
>> h.values
=> []

??
-- 
pub 1024D/8D2787EF  723C 7CA3 3C19 2ACE  6E20 9CC1 9956 EB3C 8D27 87EF