new

# File activerecord/lib/active_record/fixtures.rb, line 457
      def initialize(class_names, config)
        @class_names = class_names.stringify_keys
        @config      = config

        # Remove string values that aren't constants or subclasses of AR
        @class_names.delete_if { |k,klass|
          unless klass.is_a? Class
            klass = klass.safe_constantize
            ActiveSupport::Deprecation.warn("The ability to pass in strings as a class name to `set_fixture_class` will be removed in Rails 4.2. Use the class itself instead.")
          end
          !insert_class(@class_names, k, klass)
        }
      end