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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 repo_is_dirty(self):
 """ Return true if repo is dirty """

        try:
            subprocess.check_call(['git', 'diff-files', '--quiet'], cwd=self.repo_dir)
            # Return code is 0
            return False
        except subprocess.CalledProcessError:
            return True