def register(self, extensions):
for ext in reversed(extensions):<EOL><INDENT>for name in ext.names:<EOL><INDENT>try:<EOL><INDENT>self._extensions[name].appendleft(ext)<EOL><DEDENT>except KeyError:<EOL><INDENT>self._extensions[name] = deque([ext])<EOL><DEDENT><DEDENT><DEDENT>
Registers extensions.