def addAttachment(self, oid, file_path):
        """ Adds an attachment to a feature service
            Input:
              oid - string - OBJECTID value to add attachment to
              file_path - string - path to file
            Output:
              JSON Repsonse
        """
        if self.hasAttachments == True:
            attachURL = self._url + "/%s/addAttachment" % oid
            params = {'f':'json'}
            parsed = urlparse.urlparse(attachURL)

            files = {'attachment': file_path}
            res = self._post(url=attachURL,
                             param_dict=params,
                             files=files,
                             securityHandler=self._securityHandler,
                             proxy_port=self._proxy_port,
                             proxy_url=self._proxy_url)
            return self._unicode_convert(res)
        else:
            return "Attachments are not supported for this feature service."
Adds an attachment to a feature service
            Input:
              oid - string - OBJECTID value to add attachment to
              file_path - string - path to file
            Output:
              JSON Repsonse