python · serhiy-storchaka · Jan 23, 2026 · Jan 23, 2026
diff --git a/Doc/library/base64.rst b/Doc/library/base64.rst
@@ -239,8 +239,7 @@ Refer to the documentation of the individual functions for more information.
   *adobe* controls whether the input sequence is in Adobe Ascii85 format
   (i.e. is framed with <~ and ~>).

-   *ignorechars* should be a :term:`bytes-like object` or ASCII string
-   containing characters to ignore
+   *ignorechars* should be a byte string containing characters to ignore
   from the input. This should only contain whitespace characters, and by
   default contains all whitespace characters in ASCII.


diff --git a/Lib/test/test_base64.py b/Lib/test/test_base64.py
@@ -777,6 +777,19 @@ def test_a85decode_errors(self):
        self.assertRaises(ValueError, base64.a85decode, b'aaaay',
                          foldspaces=True)

+        self.assertEqual(base64.a85decode(b"a b\nc", ignorechars=b" \n"),
+                         b'\xc9\x89')
+        with self.assertRaises(ValueError):
+            base64.a85decode(b"a b\nc", ignorechars=b"")
+        with self.assertRaises(ValueError):
+            base64.a85decode(b"a b\nc", ignorechars=b" ")
+        with self.assertRaises(ValueError):
+            base64.a85decode(b"a b\nc", ignorechars=b"\n")
+        with self.assertRaises(TypeError):
+            base64.a85decode(b"a b\nc", ignorechars=" \n")
+        with self.assertRaises(TypeError):
+            base64.a85decode(b"a b\nc", ignorechars=None)
+
    def test_b85decode_errors(self):
        illegal = list(range(33)) + \
                  list(b'"\',./:[\\]') + \