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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_inconsistent_fieldnames():
 """ Returns a set of keys from settings.CONFIG that are not accounted for in settings.CONFIG_FIELDSETS. If there are no fieldnames in settings.CONFIG_FIELDSETS, returns an empty set. """

    field_name_list = []
    for fieldset_title, fields_list in settings.CONFIG_FIELDSETS.items():
        for field_name in fields_list:
            field_name_list.append(field_name)
    if not field_name_list:
        return {}
    return set(set(settings.CONFIG.keys()) - set(field_name_list))