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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 commit(experiment_name, time):
 """ Try to commit repo exactly as it is when starting the experiment for reproducibility. """

    try:
        sh.git.commit('-a',
                m='"auto commit tracked files for new experiment: {} on {}"'.format(experiment_name, time),
                allow_empty=True
            )
        commit_hash = sh.git('rev-parse', 'HEAD').strip()
        return commit_hash
    except:
        return '<Unable to commit>'