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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 _run_cnvkit_single(data, background=None):
 """Process a single input file with BAM or uniform background. """

    if not background:
        background = []
    ckouts = _run_cnvkit_shared([data], background)
    if not ckouts:
        return [data]
    else:
        assert len(ckouts) == 1
        return _associate_cnvkit_out(ckouts, [data])