def METHOD_NAME(receiver_list):
	validated_receiver_list = []
	for d in receiver_list:
		if not d:
			break
		# remove invalid character
		for x in [" ", "-", "(", ")"]:
			d = d.replace(x, "")
		validated_receiver_list.append(d)
	if not validated_receiver_list:
		throw(_("Please enter valid mobile nos"))
	return validated_receiver_list