# File lib/mime/types.rb, line 682
    def add(*types)
      types.each do |mime_type|
        if @type_variants.include?(mime_type.simplified)
          if @type_variants[mime_type.simplified].include?(mime_type)
            warn "Type #{mime_type} already registered as a variant of #{mime_type.simplified}."
          end
        end
        add_type_variant(mime_type)
        index_extensions(mime_type)
      end
    end