code: 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)
docs: 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.