diff --git a/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py b/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
index 7b1014ba..f43c72fe 100644
--- a/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
+++ b/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
@@ -21,7 +21,7 @@
 HEADER = f"# This file is generated by `{cli_name}`."
 
 
-def delete_existing_files(root="."):
+def delete_existing_files(root: str) -> None:
     """Delete any files generated by this generator.
 
     This function can be used to clean up a directory tree before generating a new set
@@ -30,7 +30,7 @@ def delete_existing_files(root="."):
     Parameters
     ----------
     root : str
-        The path to the root of the directory tree to search for files to delete.
+        The path (relative or absolute) to the root of the directory tree to search for files to delete.
     """
     for dirpath, _, filenames in os.walk(root):
         for fn in filter(