         deletedKeys.append(item)
     for deletedKey in deletedKeys
       @value.pop(deletedKey)
+    return @
   
   __init__: ->
     
   __ior__: (set) ->
     for item in set
       @add(item)
+    return @
   
   __isub__: (set) ->
     for item in set
       if @__contains__(item)
         @pop(item)
+    return @
 
   __iter__: ->
     return new Iterator(@)

    union.append(item) for item in @value
    union.append(item) for item in set
    return new Set(union)
    
  # Checks to see if this and set are disjoint, meaning this intersected with set is the empty set 
  isdisjoint: (set) ->
    return @__and__(set).__len__() == 0

    @clear()
    for item in xorKeys
        @add(item)
    return @

  # Checks to see if this is a subset of set
  __le__: (set) ->
