make the get_prim_callable utility a bit more fail-safe

1 files changed, 5 insertions, 1 deletions

diff --git a/TurtleArt/talogo.py b/TurtleArt/talogo.py
index b344abe..f4cd7ea 100644
--- a/TurtleArt/talogo.py
+++ b/TurtleArt/talogo.py
@@ -209,7 +209,11 @@ class LogoCode:
 
     def get_prim_callable(self, name):
         """ Return the callable primitive associated with the given name """
-        return self.oblist[name].fcn
+        sym = self.oblist.get(name)
+        if sym is not None:
+            return sym.fcn
+        else:
+            return None
 
     def run_blocks(self, code):
         """Run code generated by generate_code().