A couple of fixes to lab exercise in Chapter 3 (#225)

* correct parameter name for API: `sex_Male` -> `sex_male`

* pass request body json as a list of a list

chapters/sec1/1-3-data-access.qmd

@@ -656,7 +656,7 @@ def server(input, output, session):
     def vals():
         d = {
             "bill_length_mm" : input.bill_length(),
-            "sex_Male" : input.sex() == "Male",
+            "sex_male" : input.sex() == "Male",
             "species_Gentoo" : input.species() == "Gentoo", 
             "species_Chinstrap" : input.species() == "Chinstrap"
 
@@ -745,7 +745,7 @@ server <- function(input, output) {
   pred <- eventReactive(
     input$predict,
     httr2::request(api_url) |>
-      httr2::req_body_json(vals()) |>
+      httr2::req_body_json(list(vals())) |>
       httr2::req_perform() |>
       httr2::resp_body_json(),
     ignoreInit = TRUE