X-Git-Url: https://git.notmuchmail.org/git?a=blobdiff_plain;f=bindings%2Fpython%2Fnotmuch%2Fmessages.py;h=59ef40afee1ea2103f8273492c57b5debb4c9479;hb=b9d1045474584c7bb2c294be19c7401f78a37f62;hp=d94f91b4886b0d91fe26b90d2e3a314aa30a837b;hpb=a7561cc20b17669784c3259afcbcef98029f93e9;p=notmuch

diff --git a/bindings/python/notmuch/messages.py b/bindings/python/notmuch/messages.py
index d94f91b4..59ef40af 100644
--- a/bindings/python/notmuch/messages.py
+++ b/bindings/python/notmuch/messages.py
@@ -14,7 +14,7 @@ for more details.
 You should have received a copy of the GNU General Public License
 along with notmuch.  If not, see <http://www.gnu.org/licenses/>.
 
-Copyright 2010 Sebastian Spaeth <Sebastian@SSpaeth.de>'
+Copyright 2010 Sebastian Spaeth <Sebastian@SSpaeth.de>
                Jesse Rosenthal <jrosenthal@jhu.edu>
 """
 
@@ -172,11 +172,15 @@ class Messages(object):
     next = __next__ # python2.x iterator protocol compatibility
 
     def __nonzero__(self):
-        """
-        :return: True if there is at least one more thread in the
-            Iterator, False if not."""
-        return self._msgs is not None and \
-            self._valid(self._msgs) > 0
+        '''
+        Implement truth value testing. If __nonzero__ is not
+        implemented, the python runtime would fall back to `len(..) >
+        0` thus exhausting the iterator.
+
+        :returns: True if the wrapped iterator has at least one more object
+                  left.
+        '''
+        return self._msgs and self._valid(self._msgs)
 
     _destroy = nmlib.notmuch_messages_destroy
     _destroy.argtypes = [NotmuchMessagesP]
@@ -184,7 +188,7 @@ class Messages(object):
 
     def __del__(self):
         """Close and free the notmuch Messages"""
-        if self._msgs is not None:
+        if self._msgs:
             self._destroy(self._msgs)
 
     def format_messages(self, format, indent=0, entire_thread=False):