# File lib/mongoid/criterion/builder.rb, line 21
      def build(attrs = {})
        klass.new(
          selector.inject(attrs) do |hash, (key, value)|
            hash.tap do |attrs|
              unless key.to_s =~ /\$/ || value.is_a?(Hash)
                attrs[key] = value
              end
            end
          end
        )
      end