def METHOD_NAME(self):
    """
    Yields a function for accessing installed packages.
    """
    _open_projects = {}
    def package_loader(project_id):
        if project_id not in _open_projects:
            path = _get_data_folder().joinpath(f"packages/{project_id}")
            _open_projects[project_id] = brownie.project.load(path, project_id)
        return _open_projects[project_id]
    yield package_loader