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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 git_repo():
 """ Returns the git repository root if the cwd is in a repo, else None """

    try:
        reldir = subprocess.check_output(
            ["git", "rev-parse", "--git-dir"])
        reldir = reldir.decode("utf-8")
        return os.path.basename(os.path.dirname(os.path.abspath(reldir)))
    except subprocess.CalledProcessError:
        return None