fix type hints

src/datachain/cache.py

@@ -49,7 +49,7 @@ def __init__(self, cache_dir: str, tmp_dir: str):
             tmp_dir=tmp_dir,
         )
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         return self.odb == other.odb
 
     @property
@@ -108,13 +108,13 @@ async def download(
     def store_data(self, file: "File", contents: bytes) -> None:
         self.odb.add_bytes(file.get_hash(), contents)
 
-    def clear(self):
+    def clear(self) -> None:
         """
         Completely clear the cache.
         """
         self.odb.clear()
 
-    def destroy(self):
+    def destroy(self) -> None:
         # `clear` leaves the prefix directory structure intact.
         remove(self.cache_dir)
 

src/datachain/lib/file.py

@@ -269,7 +269,11 @@ def ensure_cached(self) -> None:
         client = self._catalog.get_client(self.source)
         client.download(self, callback=self._download_cb)
 
-    async def _prefetch(self, catalog=None, download_cb=None) -> bool:
+    async def _prefetch(
+        self,
+        catalog: Optional["Catalog"] = None,
+        download_cb: Optional["Callback"] = None,
+    ) -> bool:
         from datachain.client.hf import HfClient
 
         catalog = catalog or self._catalog

src/datachain/lib/prefetcher.py

@@ -7,13 +7,13 @@
 
 from datachain.asyn import AsyncMapper
 from datachain.cache import temporary_cache
-from datachain.catalog.catalog import Catalog
 from datachain.lib.file import File
 
 if TYPE_CHECKING:
     from contextlib import AbstractContextManager
 
     from datachain.cache import DataChainCache as Cache
+    from datachain.catalog.catalog import Catalog
 
 
 T = TypeVar("T", bound=Sequence[Any])
@@ -23,7 +23,7 @@ def noop(*args, **kwargs):
     pass
 
 
-async def _prefetch_input(row: T, catalog: Catalog, download_cb: Callback) -> T:
+async def _prefetch_input(row: T, catalog: "Catalog", download_cb: Callback) -> T:
     try:
         callback = download_cb.increment_file_count
     except AttributeError:
@@ -37,14 +37,14 @@ async def _prefetch_input(row: T, catalog: Catalog, download_cb: Callback) -> T:
     return row
 
 
-def clone_catalog_with_cache(catalog: Catalog, cache: "Cache"):
+def clone_catalog_with_cache(catalog: "Catalog", cache: "Cache") -> "Catalog":
     clone = catalog.copy()
     clone.cache = cache
     return clone
 
 
 def rows_prefetcher(
-    catalog,
+    catalog: "Catalog",
     rows: Iterable[T],
     prefetch: int,
     cache: Optional["Cache"] = None,