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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_imports(self, option):
 """ See if we have been passed a set of currencies or a setting variable or look for settings CURRENCIES or SHOP_CURRENCIES. """

        if option:
            if len(option) == 1 and option[0].isupper() and len(option[0]) > 3:
                return getattr(settings, option[0])
            else:
                codes = [e for e in option if e.isupper() and len(e) == 3]
                if len(codes) != len(option):
                    raise ImproperlyConfigured("Invalid currency codes found: %s" % codes)
                return codes
        for attr in ('CURRENCIES', 'SHOP_CURRENCIES'):
            try:
                return getattr(settings, attr)
            except AttributeError:
                continue
        return option