1 files changed, 14 insertions, 1 deletions
diff --git a/webmentions_ssg/url_security.py b/webmentions_ssg/url_security.py
index 51c037a..9cd261e 100644
--- a/webmentions_ssg/url_security.py
+++ b/webmentions_ssg/url_security.py
@@ -10,6 +10,14 @@ class AddressResolutionError(Exception):
 
 
 def is_public_url(url: str) -> bool:
+    """
+    Check whether a URL resolves exclusively to public IP addresses.
+
+    :param url: URL whose hostname should be resolved.
+    :return: Whether all resolved addresses are globally routable.
+    :raises ValueError: If the URL does not contain a hostname.
+    :raises AddressResolutionError: If the hostname cannot be resolved.
+    """
     hostname = urlsplit(url).hostname
 
     if hostname is None:
@@ -30,7 +38,12 @@ def is_public_url(url: str) -> bool:
 
 
 def is_http_url(url: str) -> bool:
-    """Return whether a URL is an absolute HTTP or HTTPS URL."""
+    """
+    Check whether a URL is an absolute HTTP or HTTPS URL.
+
+    :param url: URL to validate.
+    :return: Whether the URL uses HTTP or HTTPS and contains a hostname.
+    """
     try:
         parsed = urlsplit(url)
     except ValueError: