Fix streaming

gzip.open only works for local files, not with URLs

To open remote files in streaming mode, we extend `open` to support URLs.
This should fix https://github.com/huggingface/datasets/issues/5060

pubchem_selfies.py

@@ -472,15 +472,14 @@ class PubchemSelfies(datasets.GeneratorBasedBuilder):
     def _generate_examples(self, subdirs, split):
         # The `key` is for legacy reasons (tfds) and is not important in itself, but must be unique for each example.
         for filepath in subdirs:
-            with gzip.open(filepath, mode="rt") as f:
-                rows = f.readlines()
-            for key, row in enumerate(rows):
-                data = json.loads(row)
-                properties = data["molecules"][0]["properties"]
-                yield key, {
-                    "PUBCHEM_COMPOUND_CID": properties["PUBCHEM_COMPOUND_CID"],
-                    "PUBCHEM_OPENEYE_CAN_SMILES": properties[
-                        "PUBCHEM_OPENEYE_CAN_SMILES"
-                    ],
-                    "CAN_SELFIES": properties["CAN_SELFIES"],
-                }
+            with gzip.open(open(filepath, "rb"), "rt", encoding="utf-8") as f:
+                for key, row in enumerate(rows):
+                    data = json.loads(row)
+                    properties = data["molecules"][0]["properties"]
+                    yield key, {
+                        "PUBCHEM_COMPOUND_CID": properties["PUBCHEM_COMPOUND_CID"],
+                        "PUBCHEM_OPENEYE_CAN_SMILES": properties[
+                            "PUBCHEM_OPENEYE_CAN_SMILES"
+                        ],
+                        "CAN_SELFIES": properties["CAN_SELFIES"],
+                    }