method to revert resource to this version by issuing PATCH

		Args:
			None

		Returns:
			None: sends PATCH request, and refreshes parent resource

def revert_to(self):

		'''
		method to revert resource to this version by issuing PATCH

		Args:
			None

		Returns:
			None: sends PATCH request, and refreshes parent resource
		'''

		# send patch
		response = self.resource.repo.api.http_request('PATCH', self.uri)

		# if response 204
		if response.status_code == 204:
			logger.debug('reverting to previous version of resource, %s' % self.uri)

			# refresh current resource handle
			self._current_resource.refresh()

		else:
			raise Exception('HTTP %s, could not revert to resource version, %s' % (response.status_code, self.uri))