fold file existance check into list_files method
fold file existance check into list_files method

funginstitute/patentprocessor,nikken1/patentprocessor,funginstitute/patentprocessor,nikken1/patentprocessor,nikken1/patentprocessor,funginstitute/patentprocessor,yngcan/patentprocessor,yngcan/patentprocessor,yngcan/patentprocessor