fix mypy err

Author: BobTheBuidler

faster_web3/eth/async_eth.py

@@ -452,7 +452,7 @@ async def send_raw_transaction(self, transaction: Union[HexStr, bytes]) -> HexBy
 
     async def get_block(
         self, block_identifier: BlockIdentifier, full_transactions: bool = False
-    ) -> BlockData:
+    ) -> Union[BlockData, AttributeDict]:
         return await self._get_block(block_identifier, full_transactions)
 
     # eth_getBlockReceipts