add conditional import for couch_db work
add conditional import for couch_db work

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