    # File lib/fog/hp/models/storage/directory.rb, line 15
            def acl=(new_acl)
              if new_acl.nil?
                new_acl = "private"
              end
              valid_acls = ['private', 'public-read', 'public-write', 'public-read-write']
              unless valid_acls.include?(new_acl)
                raise ArgumentError.new("acl must be one of [#{valid_acls.join(', ')}]")
              end
              @acl = new_acl
            end