Diff of patch to pyramid_mailer

pyramid_mailer.response.diff

--- a/pyramid_mailer/response.py
+++ b/pyramid_mailer/response.py
@@ -38,6 +38,7 @@ import quopri
 import sys
 import mimetypes
 import string
+import types
 from email.mime.base import MIMEBase
 
 try:
@@ -324,8 +325,14 @@ class MailResponse(object):
             if isinstance(self.Html, MailBase):
                 part.parts.append(self.Html)
             elif self.Html:
+                try :
+                    encoded = str(self.Html)
+                except UnicodeEncodeError:
+                    (charset,charset_encoded) = encoding.best_charset(self.Html)
+                    self.Html = charset_encoded
                 part.attach_text(self.Html, 'text/html')
 
+
             for args in self.attachments:
                 self._encode_attachment(**args)