code: def empty_folder(opts)
        validate_version(VERSION_2010_SP1)
        ef_opts = {}
        [:delete_type, :delete_sub_folders].each do |k|
          ef_opts[camel_case(k)] = validate_param(opts, k, true)
        end
        fids = validate_param opts, :folder_ids, true
  
        req = build_soap! do |type, builder|
          if(type == :header)
          else
            builder.nbuild.EmptyFolder(ef_opts) {|x|
              builder.nbuild.parent.default_namespace = @default_ns
              builder.folder_ids!(fids)
            }
          end
        end
        do_soap_request(req)
      end
docs: Empties folders in a mailbox.
   @see http://msdn.microsoft.com/en-us/library/ff709484.aspx
   @param [Hash] opts
   @option opts [String] :delete_type Must be one of
     ExchangeDataServices::HARD_DELETE, SOFT_DELETE, or MOVE_TO_DELETED_ITEMS
   @option opts [Boolean] :delete_sub_folders
   @option opts [Array<Hash>] :folder_ids An array of folder_ids in the form:
     [ {:id => 'myfolderID##asdfs', :change_key => 'asdfasdf'},
       {:id => 'blah'} ]
   @todo Finish