huggingface/transformers · error · TypeError

only a single or a list of entries is supported but got type

Error message

only a single or a list of entries is supported but got type={type(image_url_or_urls)}

What it means

Error "only a single or a list of entries is supported but got type={type(image_url_or_urls)}" thrown in huggingface/transformers.

Source

Thrown at src/transformers/image_processing_base.py:487

            raise ValueError(f"{auto_class} is not a valid auto class.")

        cls._auto_class = auto_class

    def fetch_images(self, image_url_or_urls: str | list[str] | list[list[str]]):
        """
        Convert a single or a list of urls into the corresponding `PIL.Image` objects.

        If a single url is passed, the return value will be a single object. If a list is passed a list of objects is
        returned.
        """
        if isinstance(image_url_or_urls, (list, tuple)):
            return [self.fetch_images(x) for x in image_url_or_urls]
        elif isinstance(image_url_or_urls, str):
            return load_image(image_url_or_urls)
        elif is_valid_image(image_url_or_urls):
            return image_url_or_urls
        else:
            raise TypeError(f"only a single or a list of entries is supported but got type={type(image_url_or_urls)}")


ImageProcessingMixin.push_to_hub = copy_func(ImageProcessingMixin.push_to_hub)
if ImageProcessingMixin.push_to_hub.__doc__ is not None:
    ImageProcessingMixin.push_to_hub.__doc__ = ImageProcessingMixin.push_to_hub.__doc__.format(
        object="image processor", object_class="AutoImageProcessor", object_files="image processor file"
    )

View on GitHub (pinned to a597f97485)

Solutions

1. Pass a single image URL/path or a list of them.
2. Convert other iterables to a list before calling.

When it happens

Trigger: Raised in ImageProcessingMixin image loading when image_url_or_urls is neither a single entry nor a list.

Common situations: Passing a dict, tuple-of-tuples, or generator of image URLs/paths to the image loading helper.

AI-assisted analysis of huggingface/transformers@a597f97485 (2026-08-14). Data as JSON: /api/errors/5ded550332553ba8. Report an issue: GitHub.