Clarify the return value of __nonzero__(): It *must* be an integer.

Closes SF bug #579991.

diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 436fd7b472063e53886c981a4df42ae9c7281db4..911999e748d6be6384a7d278e1dcff86910f9c60 100644 (file)
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -39,9 +39,9 @@ The following values are considered false:
 
 \item  instances of user-defined classes, if the class defines a
        \method{__nonzero__()} or \method{__len__()} method, when that
-       method returns zero.\footnote{Additional information on these
-special methods may be found in the \citetitle[../ref/ref.html]{Python
-Reference Manual}.}
+       method returns the integer zero.\footnote{Additional
+information on these special methods may be found in the
+\citetitle[../ref/ref.html]{Python Reference Manual}.}
 
 \end{itemize}