fix doctest

sagemath · Mar 11, 2016 · 0391252 · 0391252
1 parent f92f927
commit 0391252
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/sage/symbolic/expression_conversions.py b/src/sage/symbolic/expression_conversions.py
@@ -752,7 +752,7 @@ def composition(self, ex, operator):
         g = ex.operands()
         import sympy
 
-        f_sympy = getattr(sympy, f, None)
+        f_sympy = getattr(sympy, f, None) or isinstance(f, sympy.core.function.UndefinedFunction)
         if f_sympy:
             return f_sympy(*sympy.sympify(g, evaluate=False))
         else: