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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 _determine_auto_detection_method():
 """Return the detection method to use when the detection method is 'auto'"""


        if dependencies.pytsk3.is_available:
            return 'pytsk3'
        elif dependencies.mmls.is_available:
            return 'mmls'
        elif dependencies.parted.is_available:
            return 'parted'
        else:
            raise PrerequisiteFailedError("No valid detection method is installed.")