Linter fix

Author: WardBrian

cmdstanpy/install_cmdstan.py

@@ -144,8 +144,11 @@ def build(verbose: bool = False) -> None:
         )
 
 
-def compile_example():
-    """Compile the example model. The current directory must be a cmdstan library."""
+def compile_example() -> None:
+    """
+    Compile the example model.
+    The current directory must be a cmdstan library.
+    """
     cmd = [
         MAKE,
         Path(