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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 _delta_dir():
 """returns the relative path of the current directory to the git repository. This path will be added the 'filename' path to find the file. It current_dir is the git root, this function returns an empty string. Keyword Arguments: <none> Returns: str -- relative path of the current dir to git root dir empty string if current dir is the git root dir """

    repo = Repo()
    current_dir = os.getcwd()
    repo_dir = repo.tree().abspath
    delta_dir = current_dir.replace(repo_dir, '')
    if delta_dir:
        return delta_dir + '/'
    else:
        return ''