diff --git a/constants.py b/constants.py
index 2e04317..b0ddc14 100644
--- a/constants.py
+++ b/constants.py
@@ -20,7 +20,10 @@ LOGCONF = {
     "root": {"level": "DEBUG", "handlers": ["console", "file"]},
 }
 
+EMAIL = "email address"
 URL = "URL"
 DOMAIN = "domain"
 IPV4 = "IPv4"
 IPV6 = "IPv6"
+
+domain_lookup = {}