code: def get_by_block(self, block_number):
          
          blocklist_snapshot = self.db.prefixed_db(NotificationPrefix.PREFIX_BLOCK).snapshot()
          block_bytes = block_number.to_bytes(4, 'little')
          results = []
          for val in blocklist_snapshot.iterator(prefix=block_bytes, include_key=False):
              event = SmartContractEvent.FromByteArray(val)
              results.append(event)
  
          return results
docs: Look up notifications for a block
          Args:
              block_number (int): height of block to search for notifications
  
          Returns:
              list: a list of notifications