Mention assert_no_globals()

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: RPiR
 Type: Package
 Title: Reproducible Programming in R
-Version: 0.76.21
+Version: 0.76.22
 Authors@R: c(person("Sonia", "Mitchell", email = "[email protected]",
                     role = c("aut"), 
                     comment = c(ORCID = "0000-0003-1536-2066")),

inst/tutorials/practical3-1/practical3-1.Rmd

@@ -447,7 +447,22 @@ For Practical 3-2 you'll need to add a function called
 with appropriate documentation. Copy the 
 <span style="color: #dd1c77;">step_deterministic_birth_death</span> function for 
 the time being, renamed of course. You'll be using this as a starting point in 
-Practical 3-2.
+Practical 3-2. You can also add a check that the functions use no
+global variables to the function definitions by adding a check at
+the bottom of the file after the end of the function.:
+
+```{r, eval = FALSE}
+}
+
+# Check for global variables
+RPiR::assert_no_globals(timestep_stochastic_birth_death)
+```
+
+We've provided a new function in the RPiR package to do the checking for
+you (`assert_no_globals()`) to make this simpler than it was in Series 2.
+You can just type `assert_no_globals` without the brackets to read the function
+definition and see that it is very similar to the code snippet we got you to
+use before.
 
 ### 2. Add a demo
 Now create a new R script called