Load your libspotify application key file.

        If called without arguments, it tries to read ``spotify_appkey.key``
        from the current working directory.

        This is an alternative to setting :attr:`application_key` yourself. The
        file must be a binary key file, not the C code key file that can be
        compiled into an application.

def load_application_key_file(self, filename=b'spotify_appkey.key'):
        """Load your libspotify application key file.

        If called without arguments, it tries to read ``spotify_appkey.key``
        from the current working directory.

        This is an alternative to setting :attr:`application_key` yourself. The
        file must be a binary key file, not the C code key file that can be
        compiled into an application.
        """
        with open(filename, 'rb') as fh:
            self.app_key = fh.read()