diff --git a/frappe/utils/data.py b/frappe/utils/data.py
index 58a161b8e6..37f28500a4 100644
--- a/frappe/utils/data.py
+++ b/frappe/utils/data.py
@@ -71,6 +71,7 @@ def get_start_of_week_index() -> int:
 
 
 def is_invalid_date_string(date_string: str) -> bool:
+	"""Returns True if the date string is invalid or None or empty."""
 	# dateutil parser does not agree with dates like "0001-01-01" or "0000-00-00"
 	return not isinstance(date_string, str) or (
 		(not date_string) or (date_string or "").startswith(("0001-01-01", "0000-00-00"))