diff --git a/contrib/linearize/linearize-data.py b/contrib/linearize/linearize-data.py
--- a/contrib/linearize/linearize-data.py
+++ b/contrib/linearize/linearize-data.py
@@ -271,7 +271,7 @@
                 else:  # If no space in cache, seek forward
                     self.inF.seek(inLen, os.SEEK_CUR)
 
-        print("Done ({} blocks written)".format((self.blkCountOut)))
+        print("Done ({} blocks written)".format(self.blkCountOut))
 
 
 if __name__ == '__main__':
diff --git a/share/qt/extract_strings_qt.py b/share/qt/extract_strings_qt.py
--- a/share/qt/extract_strings_qt.py
+++ b/share/qt/extract_strings_qt.py
@@ -80,11 +80,11 @@
 #endif
 """)
 f.write('static const char UNUSED *bitcoin_strings[] = {\n')
-f.write('QT_TRANSLATE_NOOP("bitcoin-core", "{}"),\n'.format((os.getenv('PACKAGE_NAME'),)))
-f.write('QT_TRANSLATE_NOOP("bitcoin-core", "{}"),\n'.format((os.getenv('COPYRIGHT_HOLDERS'),)))
+f.write('QT_TRANSLATE_NOOP("bitcoin-core", "{}"),\n'.format(os.getenv('PACKAGE_NAME'),))
+f.write('QT_TRANSLATE_NOOP("bitcoin-core", "{}"),\n'.format(os.getenv('COPYRIGHT_HOLDERS'),))
 if os.getenv('COPYRIGHT_HOLDERS_SUBSTITUTION') != os.getenv('PACKAGE_NAME'):
     f.write('QT_TRANSLATE_NOOP("bitcoin-core", "{}"),\n'.format(
-        (os.getenv('COPYRIGHT_HOLDERS_SUBSTITUTION'),)))
+        os.getenv('COPYRIGHT_HOLDERS_SUBSTITUTION'),))
 messages.sort(key=operator.itemgetter(0))
 for (msgid, msgstr) in messages:
     if msgid != EMPTY:
diff --git a/test/functional/test_framework/authproxy.py b/test/functional/test_framework/authproxy.py
--- a/test/functional/test_framework/authproxy.py
+++ b/test/functional/test_framework/authproxy.py
@@ -168,8 +168,8 @@
                 'code': -344,
                 'message': '{!r} RPC took longer than {} seconds. Consider '
                            'using larger timeout for calls that take '
-                           'longer to return.'.format((self._service_name,
-                                                       self.__conn.timeout))})
+                           'longer to return.'.format(self._service_name,
+                                                      self.__conn.timeout)})
         if http_response is None:
             raise JSONRPCException({
                 'code': -342, 'message': 'missing HTTP response from server'})