Provides error handling for DeviceAdmin send_message and send_bulk_message methods.

def send_messages(self, request, queryset, bulk=False):
		"""
		Provides error handling for DeviceAdmin send_message and send_bulk_message methods.
		"""
		ret = []
		errors = []
		r = ""

		for device in queryset:
			try:
				if bulk:
					r = queryset.send_message("Test bulk notification")
				else:
					r = device.send_message("Test single notification")
				if r:
					ret.append(r)
			except GCMError as e:
				errors.append(str(e))
			except APNSServerError as e:
				errors.append(e.status)
			except WebPushError as e:
				errors.append(e.message)

			if bulk:
				break

		# Because NotRegistered and InvalidRegistration do not throw GCMError
		# catch them here to display error msg.
		if not bulk:
			for r in ret:
				if "error" in r["results"][0]:
					errors.append(r["results"][0]["error"])
		else:
			try:
				errors = [r["error"] for r in ret[0][0]["results"] if "error" in r]
			except TypeError:
				for entry in ret[0][0]:
					errors = errors + [r["error"] for r in entry["results"] if "error" in r]
			except IndexError:
				pass
		if errors:
			self.message_user(
				request, _("Some messages could not be processed: %r" % (", ".join(errors))),
				level=messages.ERROR
			)
		if ret:
			if bulk:
				# When the queryset exceeds the max_recipients value, the
				# send_message method returns a list of dicts, one per chunk
				try:
					success = ret[0][0]["success"]
				except TypeError:
					success = 0
					for entry in ret[0][0]:
						success = success + entry["success"]
				if success == 0:
					return
			elif len(errors) == len(ret):
				return
			if errors:
				msg = _("Some messages were sent: %s" % (ret))
			else:
				msg = _("All messages were sent: %s" % (ret))
			self.message_user(request, msg)