def assert_raises(*args,**kwargs):
nose = import_nose()<EOL>return nose.tools.assert_raises(*args,**kwargs)<EOL>
assert_raises(exception_class, callable, *args, **kwargs)

Fail unless an exception of class exception_class is thrown
by callable when invoked with arguments args and keyword
arguments kwargs. If a different type of exception is
thrown, it will not be caught, and the test case will be
deemed to have suffered an error, exactly as for an
unexpected exception.