def METHOD_NAME(self, groupname: str, name: str) -> bool:
    """
    Checks if a bookmark with the given name exists in the given group.
    :param groupname: Group name.
    :param name: Bookmark name.
    :return: True if the bookmark exists, False otherwise.
    """
    bookmark_data = self.bookmark_data
    for folder in bookmark_data:
        items = folder.get(groupname)
        if items is not None:
            for i in items:
                if i.get(name) is not None:
                    return True
    return False