type hint

README.md

@@ -9,7 +9,7 @@ Read from the webdataset (after saving it somewhere on your disk) like this:
 
 ```python
 from webdataset import WebDataset
-from typing import TypedDict
+from typing import TypedDict, Iterable
 from PIL import Image
 from PIL.PngImagePlugin import PngImageFile
 from io import BytesIO
@@ -26,7 +26,8 @@ dataset = WebDataset('./openai-guided-diffusion-256-classcond-unguided-samples-5
 out_root = 'out'
 makedirs(out_root, exist_ok=True)
 
-for ix, item in enumerate(dataset):
+it: Iterable[Example] = iter(dataset)
+for ix, item in enumerate(it):
   with BytesIO(item['img.png']) as stream:
     img: PngImageFile = Image.open(stream)
     img.load()