No b'...'.format() method (see http://bugs.python.org/issue3982).

diff --git a/pyassuan/common.py b/pyassuan/common.py
index 2beed99b31ec46010e045e8d688f5b0ab1a93961..d3e29155cbcca23b7f04c185671d5f6fca108673 100644 (file)
--- a/pyassuan/common.py
+++ b/pyassuan/common.py
@@ -220,7 +220,7 @@ class Response (object):
     def __bytes__(self):
         if self.parameters:
             if self.type == 'D':
-                return b'{} {}'.format(b'D', self.parameters)
+                return b' '.join((b'D', self.parameters))
             else:
                 return '{} {}'.format(
                     self.type, encode(self.parameters)).encode('utf-8')