'Renders the given Form object, returning an HttpResponse.'

def render(self, form, request, step, context=None):

    old_data = request.POST
    prev_fields = []
    if old_data:
        hidden = forms.HiddenInput()
        for i in range(step):
            old_form = self.get_form(i, old_data)
            hash_name = ('hash_%s' % i)
            prev_fields.extend([bf.as_hidden() for bf in old_form])
            prev_fields.append(hidden.render(hash_name, old_data.get(hash_name, self.security_hash(request, old_form))))
    return self.render_template(request, form, ''.join(prev_fields), step, context)
