diff --git a/mwclient/util.py b/mwclient/util.py
index a18205ef79ec9410a56a6e91c5f4a0125a975feb..afa99544d954823ec1ba3045f8d7f3baee64bd42 100644
--- a/mwclient/util.py
+++ b/mwclient/util.py
@@ -3,6 +3,14 @@ import io
 
 
 def parse_timestamp(t):
+    """Parses a string containing a timestamp.
+
+    Args:
+        t (str): A string containing a timestamp.
+
+    Returns:
+        time.struct_time: A timestamp.
+    """
     if t is None or t == '0000-00-00T00:00:00Z':
         return time.struct_time((0, 0, 0, 0, 0, 0, 0, 0, 0))
     return time.strptime(t, '%Y-%m-%dT%H:%M:%SZ')