attach_list = issue.fields.attachment
print attach_list
print attach_list[0]
print attach_list[1]

[<JIRA Attachment: filename=u'test.xlsx',
               id=u'525427',
               mimeType=u'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'>, <JIRA Attachment: filename=u'test2.csv',
              id=u'525515',
              mimeType=u'application/vnd.ms-excel'> ]

    test.xlsx
    test2.csv