diff --git a/type_check_Ctup.py b/type_check_Ctup.py
index a7d2e37..a721f0d 100644
--- a/type_check_Ctup.py
+++ b/type_check_Ctup.py
@@ -29,6 +29,8 @@ def type_check_atm(self, e, env):
   
   def type_check_exp(self, e, env):
     match e:
+        case GlobalValue(id):
+          return self.type_check_atm(e, env)
         case Compare(left, [cmp], [right]) if isinstance(cmp, Is):
           l = self.type_check_exp(left, env)
           r = self.type_check_exp(right, env)