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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 add(self, *files):
 """Add one or more files to the index running git-add."""


        try:
            _run_command(("git", "add") + files)
        except CalledProcessError:
            # Only if the command fails we check if the files
            # exist, because git-add most of the time fails when
            # the provided files are not found.
            for f in files:
                if not Path(f).exists():
                    raise FileNotFoundError(f"No such file or directory: {f}")