diff --git a/swh/storage/cassandra/storage.py b/swh/storage/cassandra/storage.py
--- a/swh/storage/cassandra/storage.py
+++ b/swh/storage/cassandra/storage.py
@@ -163,12 +163,15 @@
     def content_add_metadata(self, content: List[Content]) -> Dict:
         return self._content_add(content, with_data=False)
 
-    def content_get(self, content):
-        if len(content) > BULK_BLOCK_CONTENT_LEN_MAX:
+    def content_get(
+        self, contents: List[bytes]
+    ) -> Iterable[Optional[Dict[str, bytes]]]:
+        # FIXME: Make this method support slicing the `data`.
+        if len(contents) > BULK_BLOCK_CONTENT_LEN_MAX:
             raise StorageArgumentException(
-                "Sending at most %s contents." % BULK_BLOCK_CONTENT_LEN_MAX
+                f"Send at maximum {BULK_BLOCK_CONTENT_LEN_MAX} contents."
             )
-        yield from self.objstorage.content_get(content)
+        yield from self.objstorage.content_get(contents)
 
     def content_get_partition(
         self,
diff --git a/swh/storage/in_memory.py b/swh/storage/in_memory.py
--- a/swh/storage/in_memory.py
+++ b/swh/storage/in_memory.py
@@ -251,13 +251,15 @@
     def content_add_metadata(self, content: List[Content]) -> Dict:
         return self._content_add(content, with_data=False)
 
-    def content_get(self, content):
+    def content_get(
+        self, contents: List[bytes]
+    ) -> Iterable[Optional[Dict[str, bytes]]]:
         # FIXME: Make this method support slicing the `data`.
-        if len(content) > BULK_BLOCK_CONTENT_LEN_MAX:
+        if len(contents) > BULK_BLOCK_CONTENT_LEN_MAX:
             raise StorageArgumentException(
-                "Sending at most %s contents." % BULK_BLOCK_CONTENT_LEN_MAX
+                f"Send at maximum {BULK_BLOCK_CONTENT_LEN_MAX} contents."
             )
-        yield from self.objstorage.content_get(content)
+        yield from self.objstorage.content_get(contents)
 
     def content_get_range(self, start, end, limit=1000):
         if limit is None:
diff --git a/swh/storage/interface.py b/swh/storage/interface.py
--- a/swh/storage/interface.py
+++ b/swh/storage/interface.py
@@ -146,7 +146,9 @@
         ...
 
     @remote_api_endpoint("content/data")
-    def content_get(self, content):
+    def content_get(
+        self, contents: List[bytes]
+    ) -> Iterable[Optional[Dict[str, bytes]]]:
         """Retrieve in bulk contents and their data.
 
         This generator yields exactly as many items than provided sha1
@@ -154,20 +156,22 @@
 
         It may also yield `None` values in case an object was not found.
 
+        TODO:
+            Rename to content_get_data
+
         Args:
-            content: iterables of sha1
+            contents: iterables of sha1
+
+        Raises:
+            StorageArgumentException in case of too much contents are required.
+            (cf. BULK_BLOCK_CONTENT_LEN_MAX)
 
         Yields:
-            Dict[str, bytes]: Generates streams of contents as dict with their
-                raw data:
+            Streams of contents as dict with their raw data:
 
                 - sha1 (bytes): content id
                 - data (bytes): content's raw data
 
-        Raises:
-            ValueError in case of too much contents are required.
-            cf. BULK_BLOCK_CONTENT_LEN_MAX
-
         """
         ...
 
diff --git a/swh/storage/storage.py b/swh/storage/storage.py
--- a/swh/storage/storage.py
+++ b/swh/storage/storage.py
@@ -266,13 +266,15 @@
         }
 
     @timed
-    def content_get(self, content):
+    def content_get(
+        self, contents: List[bytes]
+    ) -> Iterable[Optional[Dict[str, bytes]]]:
         # FIXME: Make this method support slicing the `data`.
-        if len(content) > BULK_BLOCK_CONTENT_LEN_MAX:
+        if len(contents) > BULK_BLOCK_CONTENT_LEN_MAX:
             raise StorageArgumentException(
-                "Send at maximum %s contents." % BULK_BLOCK_CONTENT_LEN_MAX
+                f"Send at maximum {BULK_BLOCK_CONTENT_LEN_MAX} contents."
             )
-        yield from self.objstorage.content_get(content)
+        yield from self.objstorage.content_get(contents)
 
     @timed
     @db_transaction()