python2代码升级到python3工具

python模块lib2to3(py2转py3自动化工具)

 Usage: 2to3 [options] file|dir ...

 Options:
   -h, --help            show this help message and exit
   -d, --doctests_only   Fix up doctests only
   -f FIX, --fix=FIX     Each FIX specifies a transformation; default: all
   -j PROCESSES, --processes=PROCESSES
                         Run 2to3 concurrently
   -x NOFIX, --nofix=NOFIX
                         Prevent a transformation from being run
   -l, --list-fixes      List available transformations
   -p, --print-function  Modify the grammar so that print() is a function
   -v, --verbose         More verbose logging
   --no-diffs            Don't show diffs of the refactoring
   -w, --write           Write back modified files
   -n, --nobackups       Don't write backups for modified files
   -o OUTPUT_DIR, --output-dir=OUTPUT_DIR
                         Put output files in this directory instead of
                         overwriting the input files.  Requires -n.
   -W, --write-unchanged-files
                         Also write files even if no changes were required
                         (useful with --output-dir); implies -w.
   --add-suffix=ADD_SUFFIX
                         Append this string to all output filenames. Requires
                         -n if non-empty.  ex: --add-suffix='' will generate
                         .py3 files.

eg:2to3 -w test.py