:class:`tzinfo` Objects
-----------------------
-:class:`tzinfo` is an abstract base clase, meaning that this class should not be
+:class:`tzinfo` is an abstract base class, meaning that this class should not be
instantiated directly. You need to derive a concrete subclass, and (at least)
supply implementations of the standard :class:`tzinfo` methods needed by the
:class:`datetime` methods you use. The :mod:`datetime` module does not supply
is printed to ``sys.stderr`` instead. Also, when :meth:`__del__` is invoked in
response to a module being deleted (e.g., when execution of the program is
done), other globals referenced by the :meth:`__del__` method may already have
- been deleted. For this reason, :meth:`__del__` methods should do the absolute
+ been deleted or in the process of being torn down (e.g. the import
+ machinery shutting down). For this reason, :meth:`__del__` methods
+ should do the absolute
minimum needed to maintain external invariants. Starting with version 1.5,
Python guarantees that globals whose name begins with a single underscore are
deleted from their module before other globals are deleted; if no other