checking for None for checkpoint

datasets/nfts/nfts/cli.py

@@ -76,7 +76,7 @@ def handle_materialize(args: argparse.Namespace) -> None:
             moonstream_datastore, args.blockchain.value
         )
         logger.info(f"Last saved block: {last_saved_block}")
-        if last_saved_block >= bounds.starting_block:
+        if last_saved_block and last_saved_block >= bounds.starting_block:
             logger.info(
                 f"Skipping blocks {bounds.starting_block}-{last_saved_block}, starting from {last_saved_block + 1}"
             )

datasets/nfts/nfts/datastore.py

@@ -380,7 +380,9 @@ def insert_events(
     conn.commit()
 
 
-def get_last_saved_block(conn: sqlite3.Connection, blockchain_type: str) -> int:
+def get_last_saved_block(
+    conn: sqlite3.Connection, blockchain_type: str
+) -> Optional[int]:
     """
     Returns the last block number that was saved to the database.
     """
@@ -390,8 +392,6 @@ def get_last_saved_block(conn: sqlite3.Connection, blockchain_type: str) -> int:
 
     cur.execute(query)
     result = cur.fetchone()
-    if result is None:
-        return 0
 
     return result[0]