gistfile1.txt

LOLcalhost :: ~ % pry                                                                                                                                                                                                                     1 ↵
[1] pry(main)> foo = {}
=> {}
[2] pry(main)> foo.default= []
=> []
[3] pry(main)> foo['asdfsdf']
=> []
[4] pry(main)> foo['bar'].push '1'
=> ["1"]
[5] pry(main)> foo
=> {}
[6] pry(main)> foo['bar']
=> ["1"]
[7] pry(main)> foo.keys
=> []
[8] pry(main)> foo.inspect
=> "{}"