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| -rw-r--r-- | Doc/reference/datamodel.rst | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst index d083af5..0c1a10e 100644 --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -1424,11 +1424,12 @@ Basic customization .. index:: single: __len__() (mapping object method) - Called to implement truth value testing, and the built-in operation ``bool()``; + Called to implement truth value testing and the built-in operation ``bool()``; should return ``False`` or ``True``, or their integer equivalents ``0`` or - ``1``. When this method is not defined, :meth:`__len__` is called, if it is - defined (see below). If a class defines neither :meth:`__len__` nor - :meth:`__nonzero__`, all its instances are considered true. + ``1``. When this method is not defined, :meth:`__len__` is called, if it is + defined, and the object is considered true if its result is nonzero. + If a class defines neither :meth:`__len__` nor :meth:`__nonzero__`, all its + instances are considered true. .. method:: object.__unicode__(self) |