Add unicode support by replacing str() with unicode() and using utf-8.
Add unicode support by replacing str() with unicode() and using utf-8.

str() will not accept non ASCII characters, such as Δ.
"encoding='utf-8" argument passed to tostring() ensure XML is encoded as utf-8, as per Clockwork SMS API.
Does not enforce character set (http://www.clockworksms.com/doc/reference/faqs/gsm-character-set/).

mediaburst/clockwork-python