diff --git a/ch07-case-study/case_study.Rmd b/ch07-case-study/case_study.Rmd
index dd1b2944..82917202 100644
--- a/ch07-case-study/case_study.Rmd
+++ b/ch07-case-study/case_study.Rmd
@@ -123,10 +123,10 @@ prediction <- renderText({
                          LATITUDE = input$LATITUDE,
                          LONGITUDE = input$LONGITUDE)
   
-  clf$predict(r_to_py(input_df))
+  py$clf$predict(r_to_py(input_df))
 })
 ```
 
 The fire cause code is `r prediction`.
 
-## {-}
\ No newline at end of file
+## {-}