# File lib/mail/attachments_list.rb, line 39
    def []=(name, value)
      encoded_name = Mail::Encodings.decode_encode name, :encode
      default_values = { :content_type => "#{set_mime_type(name)}; filename=\"#{encoded_name}\"",
                         :content_transfer_encoding => "#{guess_encoding}",
                         :content_disposition => "#{@content_disposition_type}; filename=\"#{encoded_name}\"" }

      if value.is_a?(Hash)

        default_values[:body] = value.delete(:content) if value[:content]

        default_values[:body] = value.delete(:data) if value[:data]

        encoding = value.delete(:transfer_encoding) || value.delete(:encoding)
        if encoding
          if Mail::Encodings.defined? encoding
            default_values[:content_transfer_encoding] = encoding
          else
            raise "Do not know how to handle Content Transfer Encoding #{encoding}, please choose either quoted-printable or base64"
          end
        end

        if value[:mime_type]
          default_values[:content_type] = value.delete(:mime_type)
          @mime_type = MIME::Types[default_values[:content_type]].first
          default_values[:content_transfer_encoding] = guess_encoding
        end

        hash = default_values.merge(value)
      else
        default_values[:body] = value
        hash = default_values
      end

      if hash[:body].respond_to? :force_encoding and hash[:body].respond_to? :valid_encoding?
        if not hash[:body].valid_encoding? and default_values[:content_transfer_encoding].downcase == "binary"
          hash[:body].force_encoding("BINARY")
        end
      end

      attachment = Part.new(hash)
      attachment.add_content_id(hash[:content_id])

      @parts_list << attachment
    end