'Post step form data to `url`, using supplementary `kwargs`
Use data from kwargs to build dict to pass into form'

@patch('readthedocs.projects.views.private.trigger_build', (lambda x, basic: None))
def post_step(self, step, **kwargs):

    if (not self.url):
        raise Exception('Missing    wizard    URL')
    try:
        data = dict((('{0}-{1}'.format(step, k), v) for (k, v) in list(self.step_data[step].items())))
    except KeyError:
        pass
    data['{0}-current_step'.format(self.wizard_class_slug)] = step
    view = self.wizard_class.as_view()
    req = self.request(self.url, method='post', data=data, **kwargs)
    resp = view(req)
    self.assertIsNotNone(resp)
    return resp
