How to use the restless.constants.NO_CONTENT function in restless

* ``delete_list`` (requires authentication)

    Users may also wish to define a ``fields`` attribute on the class. By
    providing a dictionary of output names mapped to a dotted lookup path, you
    can control the serialized output.

    Users may also choose to override the ``status_map`` and/or ``http_methods``
    on the class. These respectively control the HTTP status codes returned by
    the views and the way views are looked up (based on HTTP method & endpoint).
    """
    status_map = {
        'list': OK,
        'detail': OK,
        'create': CREATED,
        'update': ACCEPTED,
        'delete': NO_CONTENT,
        'update_list': ACCEPTED,
        'create_detail': CREATED,
        'delete_list': NO_CONTENT,
    }
    http_methods = {
        'list': {
            'GET': 'list',
            'POST': 'create',
            'PUT': 'update_list',
            'DELETE': 'delete_list',
        },
        'detail': {
            'GET': 'detail',
            'POST': 'create_detail',
            'PUT': 'update',
            'DELETE': 'delete',

def build_response(self, data, status=OK):
        if status == NO_CONTENT:
            # Avoid crashing the client when it tries to parse nonexisting JSON.
            content_type = 'text/plain'
        else:
            content_type = 'application/json'
        self.ref_rh.set_header("Content-Type", "{}; charset=UTF-8"
                               .format(content_type))

        self.ref_rh.set_status(status)
        self.ref_rh.finish(data)

def build_response(self, data, status=OK):
        if status == NO_CONTENT:
            # Avoid crashing the client when it tries to parse nonexisting JSON.
            content_type = 'text/plain'
        else:
            content_type = 'application/json'
        resp = HttpResponse(data, content_type=content_type, status=status)
        return resp

def build_response(self, data, status=OK):
        if status == NO_CONTENT:
            # Avoid crashing the client when it tries to parse nonexisting JSON.
            content_type = 'text/plain'
        else:
            content_type = 'application/json'
        resp = Response(data, status_code=status, content_type=content_type)
        return resp

def build_response(self, data, status=OK):
        if status == NO_CONTENT:
            # Avoid crashing the client when it tries to parse nonexisting JSON.
            content_type = 'text/plain'
        else:
            content_type = 'application/json'
        return make_response(data, status, {
            'Content-Type': content_type,
        })