Issue #15167 (as part of #13959): imp.get_magic() is no implemented in
Lib/imp.py.
diff --git a/Doc/c-api/import.rst b/Doc/c-api/import.rst
index 1f6b1e8..2d0d1b5 100644
--- a/Doc/c-api/import.rst
+++ b/Doc/c-api/import.rst
@@ -172,7 +172,10 @@
Return the magic number for Python bytecode files (a.k.a. :file:`.pyc` and
:file:`.pyo` files). The magic number should be present in the first four bytes
- of the bytecode file, in little-endian byte order.
+ of the bytecode file, in little-endian byte order. Returns -1 on error.
+
+ .. versionchanged:: 3.3
+ Return value of -1 upon failure.
.. c:function:: const char * PyImport_GetMagicTag()