fix: JSON parsing error

wumpus/wumpus.py

@@ -272,7 +272,7 @@ class WumpusWorld(GridWorld):
             else:
                 return [getCoord(data)]
 
-        size = next(coordLst('size'))
+        size = getCoord(desc.get('size', [8, 8]))
         blocks = coordLst('blocks')
         hunters = desc.get('hunters', [])
         pits = coordLst('pits')