diff --git a/src/type.jl b/src/type.jl
index f654302..f97f99c 100644
--- a/src/type.jl
+++ b/src/type.jl
@@ -306,7 +306,7 @@ function sommelier(
 end
 
 
-mutable f virtualcustomer <: agent
+mutable struct virtualcustomer <: agent
   name::String  # agent name
   id::String    # agent id
   systemmsg::String # system message