python: fix NULL pointer tests

Fix the NULL pointer tests in the destructors of all classes and
Database.create.

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>

bindings/python/notmuch/database.py

@@ -189,7 +189,7 @@ class Database(object):
         :raises: :exc:`NotmuchError` in case of any failure
                     (possibly after printing an error message on stderr).
         """
-        if self._db is not None:
+        if self._db:
             raise NotmuchError(message="Cannot create db, this Database() "
                                        "already has an open one.")
 

bindings/python/notmuch/directory.py

@@ -181,5 +181,5 @@ class Directory(object):
 
     def __del__(self):
         """Close and free the Directory"""
-        if self._dir_p is not None:
+        if self._dir_p:
             self._destroy(self._dir_p)

bindings/python/notmuch/filenames.py

@@ -128,7 +128,7 @@ class Filenames(Python3StringMixIn):
 
     def __del__(self):
         """Close and free the notmuch filenames"""
-        if self._files_p is not None:
+        if self._files_p:
             self._destroy(self._files_p)
 
     def __len__(self):

bindings/python/notmuch/message.py

@@ -741,5 +741,5 @@ class Message(Python3StringMixIn):
 
     def __del__(self):
         """Close and free the notmuch Message"""
-        if self._msg is not None:
+        if self._msg:
             self._destroy(self._msg)

bindings/python/notmuch/messages.py

@@ -184,7 +184,7 @@ 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):

bindings/python/notmuch/query.py

@@ -203,5 +203,5 @@ class Query(object):
 
     def __del__(self):
         """Close and free the Query"""
-        if self._query is not None:
+        if self._query:
             self._destroy(self._query)

bindings/python/notmuch/tag.py

@@ -137,5 +137,5 @@ class Tags(Python3StringMixIn):
 
     def __del__(self):
         """Close and free the notmuch tags"""
-        if self._tags is not None:
+        if self._tags:
             self._destroy(self._tags)

bindings/python/notmuch/thread.py

@@ -260,5 +260,5 @@ class Thread(object):
 
     def __del__(self):
         """Close and free the notmuch Thread"""
-        if self._thread is not None:
+        if self._thread:
             self._destroy(self._thread)

bindings/python/notmuch/threads.py

@@ -176,5 +176,5 @@ class Threads(Python3StringMixIn):
 
     def __del__(self):
         """Close and free the notmuch Threads"""
-        if self._threads is not None:
+        if self._threads:
             self._destroy(self._threads)