def get_authorization(self):
        """
        Get the username and password for Basic authentication header.
        :return Authentication: The authentication data or None if it is not present or invalid.
        """
        auth = get_authorization_header()

        if not auth:
            return None

        auth_type, auth_info = auth

        if auth_type != b'basic':
            return None

        try:
            username, password = base64.b64decode(auth_info).split(b':', 1)
        except Exception:
            return None

        return Authorization('basic', username=bytes_to_wsgi(username), password=bytes_to_wsgi(password))