db lazyitem fix

src/dexorder/blockstate/db_state.py

@@ -5,7 +5,7 @@ from dexorder.blockstate.fork import Fork
 from . import BlockSet, BlockDict, BlockState, DataType
 from .blockdata import BlockData, SeriesCollection
 from .diff import DiffItem, DiffEntryItem
-from .. import db, DELETE
+from .. import db, DELETE, NARG
 from ..base.chain import current_chain
 from ..blocks import get_block
 from ..database.model import SeriesSet, SeriesDict
@@ -32,6 +32,8 @@ class DbState(SeriesCollection):
         series = var.series2str(var.series)
         key = var.key2str(item)
         value = db.session.get(Entity, (chain_id, series, key))
+        if value is None:
+            return NARG
         return var.str2value(value.value)
 
     def finalize(self, fork: Fork, diffs: Iterable[Union[DiffItem,DiffEntryItem]]):