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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 make_vol_opt(hostdir, contdir, options=None):
    '''Generate a docker volume option'''
    vol = '--volume={}:{}'.format(hostdir, contdir)
    if options != None:
        if isinstance(options, str):
            options = (options,)
        vol += ':' + ','.join(options)
    return vol