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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 unload(filename):
 """ Unload a SPICE kernel. http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/unload_c.html :param filename: The name of a kernel to unload. :type filename: str """

    if isinstance(filename, list):
        for f in filename:
            libspice.unload_c(stypes.stringToCharP(f))
        return
    filename = stypes.stringToCharP(filename)
    libspice.unload_c(filename)