TypeError: object of type 'module' has no len()

`python
def init(self, data_source: Sized, replacement: bool = False,
num_samples: Optional[int] = None, generator=None) -> None:
self.data_source = data_source
self.replacement = replacement
self._num_samples = num_samples
self.generator = generator

    if not isinstance(self.replacement, bool):
        raise TypeError("replacement should be a boolean value, but got "
                        "replacement={}".format(self.replacement))

    if not isinstance(self.num_samples, int) or self.num_samples <= 0:
        raise ValueError("num_samples should be a positive integer "
                         "value, but got num_samples={}".format(self.num_samples))

@property
def num_samples(self) -> int:
    # dataset size might change at runtime
    if self._num_samples is None:
        return len(self.data_source)     #这里报错
    return self._num_samples

def __iter__(self) -> Iterator[int]:
    n = len(self.data_source)
    if self.generator is None:
        seed = int(torch.empty((), dtype=torch.int64).random_().item())
        generator = torch.Generator()
        generator.manual_seed(seed)
    else:
        generator = self.generator

    if self.replacement:
        for _ in range(self.num_samples // 32):
            yield from torch.randint(high=n, size=(32,), dtype=torch.int64, generator=generator).tolist()
        yield from torch.randint(high=n, size=(self.num_samples % 32,), dtype=torch.int64, generator=generator).tolist()
    else:
        for _ in range(self.num_samples // n):
            yield from torch.randperm(n, generator=generator).tolist()
        yield from torch.randperm(n, generator=generator).tolist()[:self.num_samples % n]

def __len__(self) -> int:
    return self.num_samples

in num_samples

return len(self.data_source)

TypeError: object of type 'module' has no len()

请问这个要怎么解决呢？

__len__改为len