def check_and_get_specific_output_format(obj, data=None, filename=None):

    if obj.request.query_params and 'output_format' in obj.request.query_params and obj.request.query_params['output_format'] == 'xlsx':

        if not data:
            serializer = obj.get_serializer(obj.get_queryset(), many=True)
            data = serializer.data

        from .api_export_xls import xls_export
        return xls_export(data, filename)

    return None

def fix_txt_for_use_in_interlinks(txt):
    txt = txt.replace('/', ' ')
    txt = txt.replace('?', ' ')
    txt = txt.replace(';', ' ')
    txt = txt.replace(',', ' ')
    txt = txt.replace('+', ' ')
    txt = txt.replace(':', ' ')
    return txt