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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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()