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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 db_is_indexing(cls, impl, working_dir):
 """ Is the system indexing? Return True if so, False if not. """

        indexing_lockfile_path = config.get_lockfile_filename(impl, working_dir)
        return os.path.exists(indexing_lockfile_path)