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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_set(var):
    '''
    Force var to be a set
    '''
    if var is None:
        return set()
    if not isinstance(var, list):
        if isinstance(var, six.string_types):
            var = var.split()
        else:
            var = list(var)
    return set(var)