+Note: When a key contains dots ".", it is converted to a nested
+map. If empty element appears as a result of split, such as when
+a dot is at the beginning or at the end of the key, or there are
+consequitive dots, such elemets are ignored. For example,
+
+```
+"map": { "www.uk": { "alias" : "www.example.co.uk" }
+ , "www..us": { "alias" : "www.example.com" }
+ , "smtp.us.": { "alias" : "smtp.example.com" }
+```
+
+is equivalent to
+
+```
+"map": { "uk": { "map": { "www": { "alias" : "www.example.co.uk" }}}
+ , "us": { "map": { "www": { "alias" : "www.example.com" }
+ , "smtp": { "alias" : "smtp.example.com" }}
+ }
+ }
+```
+