Improve behaviour when neither settings path or file_path are defined
Improve behaviour when neither settings path or file_path are defined

pahko/isort,wimglenn/isort,jamesbroadhead/isort,PyCQA/isort,tomviner/isort,jmullan/isort,AbsoluteMSTR/isort,gforcada/isort,AbsoluteMSTR/isort,gforcada/isort,levic/isort,PyCQA/isort,leepa/isort,jamesbroadhead/isort,graingert/isort,leepa/isort,adamchainz/isort,tomviner/isort,aequitas/isort,jmullan/isort,pahko/isort,adamchainz/isort,aequitas/isort,wimglenn/isort,levic/isort,graingert/isort