diff --git a/Lib/warnings.py b/Lib/warnings.py
index 5df3f49..9de2c67 100644
--- a/Lib/warnings.py
+++ b/Lib/warnings.py
@@ -32,7 +32,14 @@
                    append=False):
     """Insert an entry into the list of warnings filters (at the front).
 
-    Use assertions to check that all arguments have the right type."""
+    'action' -- one of "error", "ignore", "always", "default", "module",
+                or "once"
+    'message' -- a regex that the warning message must match
+    'category' -- a class that the warning must be a subclass of
+    'module' -- a regex that the module name must match
+    'lineno' -- an integer line number, 0 matches all warnings
+    'append' -- if true, append to the list of filters
+    """
     import re
     assert action in ("error", "ignore", "always", "default", "module",
                       "once"), "invalid action: %r" % (action,)
@@ -53,6 +60,11 @@
     """Insert a simple entry into the list of warnings filters (at the front).
 
     A simple filter matches all modules and messages.
+    'action' -- one of "error", "ignore", "always", "default", "module",
+                or "once"
+    'category' -- a class that the warning must be a subclass of
+    'lineno' -- an integer line number, 0 matches all warnings
+    'append' -- if true, append to the list of filters
     """
     assert action in ("error", "ignore", "always", "default", "module",
                       "once"), "invalid action: %r" % (action,)