Enhance issubclass() and PyObject_IsSubclass() so that a tuple is

supported as the second argument. This has the same meaning as
for isinstance(), i.e. issubclass(X, (A, B)) is equivalent
to issubclass(X, A) or issubclass(X, B). Compared to isinstance(),
this patch does not search the tuple recursively for classes, i.e.
any entry in the tuple that is not a class, will result in a
TypeError.

This closes SF patch #649608.

1 files changed, 7 insertions, 5 deletions

diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex
index fd9092d..4716dd2 100644
--- a/Doc/lib/libfuncs.tex
+++ b/Doc/lib/libfuncs.tex
@@ -550,11 +550,13 @@ def my_import(name):
   \versionchanged[Support for a tuple of type information was added]{2.2}
 \end{funcdesc}
 
-\begin{funcdesc}{issubclass}{class1, class2}
-  Return true if \var{class1} is a subclass (direct or indirect) of
-  \var{class2}.  A class is considered a subclass of itself.  If
-  either argument is not a class object, a \exception{TypeError}
-  exception is raised.
+\begin{funcdesc}{issubclass}{class, classinfo}
+  Return true if \var{class} is a subclass (direct or indirect) of
+  \var{classinfo}.  A class is considered a subclass of itself.
+  \var{classinfo} may be a tuple of class objects, in which case every
+  entry in \var{classinfo} will be checked. In any other case, a
+  \exception{TypeError} exception is raised.
+  \versionchanged[Support for a tuple of type information was added]{2.3}
 \end{funcdesc}
 
 \begin{funcdesc}{iter}{o\optional{, sentinel}}