# File lib/mime/types.rb, line 402
      def from_mime_type(mime_type) #:yields the new MIME::Type:
        m = MIME::Type.new(mime_type.content_type.dup) do |t|
          t.extensions = mime_type.extensions.map { |e| e.dup }
          t.url = mime_type.url && mime_type.url.map { |e| e.dup }

          mime_type.system && t.system = mime_type.system.dup
          mime_type.encoding && t.encoding = mime_type.encoding.dup

          t.obsolete = mime_type.obsolete?
          t.registered = mime_type.registered?

          mime_type.docs && t.docs = mime_type.docs.dup
          
        end

        yield m if block_given?
      end