   #
   # Returns promise for boolean
   sismember: (key, value) ->
-    set = @data.get(@key(key))
+    set = @_data.get(@key(key))
     if not set
       Q(null)
     else

  # Returns promise an Array of User instances matching the fuzzy name.
  usersForRawFuzzyName: (fuzzyName) ->
    lowerFuzzyName = fuzzyName.toLowerCase()
    users = _.filter @users.values(), (user) ->
      user.name.toLowerCase().lastIndexOf(lowerFuzzyName, 0) is 0

    Q(users)

  # Returns promise
  linsert: (key, placement, pivot, value) ->
    key = @key(key)
    list = @_data.get(key)

    if list isnt undefined
      pivot = @serialize(pivot)
