'Returns the application iterator for the given environ.  Depending
on the request method and the current status code the return value
might be an empty response rather than the one from the response.
If the request method is `HEAD` or the status code is in a range
where the HTTP specification requires an empty response, an empty
iterable is returned.
.. versionadded:: 0.6
:param environ: the WSGI environment of the request.
:return: a response iterable.'

def get_app_iter(self, environ):

    status = self.status_code
    if ((environ['REQUEST_METHOD'] == 'HEAD') or (100 <= status < 200) or (status in (204, 304))):
        iterable = ()
    elif self.direct_passthrough:
        if __debug__:
            _warn_if_string(self.response)
        return self.response
    else:
        iterable = self.iter_encoded()
    return ClosingIterator(iterable, self.close)
