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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 unfreeze_extensions(self):
 """Remove a previously frozen list of extensions."""


        output_path = os.path.join(_registry_folder(), 'frozen_extensions.json')
        if not os.path.isfile(output_path):
            raise ExternalError("There is no frozen extension list")

        os.remove(output_path)
        ComponentRegistry._frozen_extensions = None