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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_process_mapping():
 """Select a way to obtain process information from the system. * `/proc` is used if supported. * The system `ps` utility is used as a fallback option. """

    for impl in (proc, ps):
        try:
            mapping = impl.get_process_mapping()
        except EnvironmentError:
            continue
        return mapping
    raise ShellDetectionFailure('compatible proc fs or ps utility is required')