From 1181042ee09720a6c50a97e493d10b07e45b3911 Mon Sep 17 00:00:00 2001
From: Salvo 'LtWorf' Tomaselli <tiposchi@tiscali.it>
Date: Wed, 26 Aug 2020 17:15:51 +0200
Subject: [PATCH] Handle empty context

---
 relational/optimizer.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/relational/optimizer.py b/relational/optimizer.py
index 178da5f..ea2599d 100644
--- a/relational/optimizer.py
+++ b/relational/optimizer.py
@@ -137,7 +137,7 @@ def general_optimize(expression):
     return optimize_all(expression, None, specific=False, general=True)
 
 
-def recursive_scan(function, node, rels) -> Tuple[Node, int]:
+def recursive_scan(function, node: Node, rels: Optional[Dict[str, Any]]) -> Tuple[Node, int]:
     '''Does a recursive optimization on the tree.
 
     This function will recursively execute the function given
@@ -151,7 +151,7 @@ def recursive_scan(function, node, rels) -> Tuple[Node, int]:
     returned value.'''
 
     args = []
-    if rels:
+    if rels is not None:
         args.append(rels)
 
     changes = 0