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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_library_root_key_for_os_path(self, path):
 """Return library root key if path is within library root paths"""

        path = os.path.realpath(path)
        library_root_key = None
        for library_root_key, library_root_path in self._library_root_paths.items():
            rel_path = os.path.relpath(path, library_root_path)
            if rel_path.startswith('..'):
                library_root_key = None
                continue
            else:
                break
        return library_root_key