async def METHOD_NAME(self) -> None:
    await super(TestGroupBy, self).METHOD_NAME()
    self.a1 = await Author.create(name="author1")
    self.a2 = await Author.create(name="author2")
    for i in range(10):
        await Book.create(name=f"book{i}", author=self.a1, rating=i)
    for i in range(5):
        await Book.create(name=f"book{i}", author=self.a2, rating=i)