X-Git-Url: https://git.notmuchmail.org/git?a=blobdiff_plain;f=bindings%2Fpython%2Fnotmuch%2Fmessages.py;h=59ef40afee1ea2103f8273492c57b5debb4c9479;hb=2ef24acf03fdd73e39d2c233016e71f194affbcf;hp=20d3632955bb3808c4e9c32edca14c28d73c0e4e;hpb=69f077898a65c10453d08dd94bf4c94efc69b91b;p=notmuch

diff --git a/bindings/python/notmuch/messages.py b/bindings/python/notmuch/messages.py
index 20d36329..59ef40af 100644
--- a/bindings/python/notmuch/messages.py
+++ b/bindings/python/notmuch/messages.py
@@ -14,18 +14,20 @@ 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>
 """
 
 from .globals import (
     nmlib,
-    NullPointerError,
-    NotInitializedError,
     NotmuchTagsP,
     NotmuchMessageP,
     NotmuchMessagesP,
 )
+from .errors import (
+    NullPointerError,
+    NotInitializedError,
+)
 from .tag import Tags
 from .message import Message
 
@@ -170,11 +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]
@@ -182,7 +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):