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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 unstaged():
 # type: () -> List[str] """ Return a list of unstaged files in the project repository. Returns: list[str]: The list of files not tracked by project git repo. """

    with conf.within_proj_dir():
        status = shell.run(
            'git status --porcelain',
            capture=True,
            never_pretend=True
        ).stdout
        results = []

        for file_status in status.split(os.linesep):
            if file_status.strip() and file_status[0] == ' ':
                results.append(file_status[3:].strip())

        return results