diff --git a/src/sage/symbolic/callable.py b/src/sage/symbolic/callable.py
index 42d24bbce5f..5f3a7bea659 100644
--- a/src/sage/symbolic/callable.py
+++ b/src/sage/symbolic/callable.py
@@ -307,7 +307,7 @@ def _coerce_map_from_(self, R):
             sage: g.parent().has_coerce_map_from(f.parent())
             True
         """
-        if isinstance(R, CallableSymbolicExpressionRing):
+        if isinstance(R, CallableSymbolicExpressionRing_class):
             args = self.arguments()
             if all(a in args for a in R.arguments()):
                 return True