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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 get_git_file_path(filename):
 """ Get relative path for filename in git root. :param filename: File name :return: relative path or None """

    git_root = get_git_root(filename)
    return relpath(filename, git_root).replace("\\", "/") if git_root else ''