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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 validate(export_formats):
 """Validates export_formats. Raises: ValueError if the format is unknown. """

        for i in range(len(export_formats)):
            export_formats[i] = export_formats[i].strip().lower()
            if export_formats[i] not in [
                    ExportFormat.CHECKPOINT, ExportFormat.MODEL
            ]:
                raise TuneError("Unsupported export format: " +
                                export_formats[i])