anchor.diff:  
   rem script flags
   set "FLAG_VALUE_PREFIX_DIRS=__pycache__"
  -set "FLAG_VALUE_SUFFIX_NAMES=.cpython-36|.cpython-35|.cpython-34|.cpython-33|.cpython-32"
  +rem default list of suffixes
  +set "FLAG_VALUE_SUFFIX_NAMES=.cpython-39|.cpython-38|.cpython-37|.cpython-36|.cpython-35|.cpython-34|.cpython-33|.cpython-32|.cpython-31|.cpython-30"
   
   :FLAGS_LOOP
   
  
positive.code: 
  if not "%FLAG%" == "" (
    if "%FLAG%" == "-prefix_dirs" (
      shift
      call set "FLAG_VALUE_PREFIX_DIRS=%%~1"
      shift
    ) else if "%FLAG%" == "-suffix_names" (
      shift
      call set "FLAG_VALUE_SUFFIX_NAMES=%%~1"
      shift
    ) else (
      echo.%?~nx0%: error: invalid flag: %FLAG%
  
negative.code: rem
  rem Examples:
  rem   1. mkdir "c:\Python36\Lib\site-packages.pycache_copy"
  rem      call copy_pycache.bat "c:\Python36\Lib\site-packages" "c:\Python36\Lib\site-packages.pycache_copy"
  rem   2. mkdir "c:\Python36\Lib\site-packages.pycache_copy"
  rem      call copy_pycache.bat -prefix_dirs "__pycache__|__pycache__/37" -suffix_names ".cpython-37" "c:\Python36\Lib\site-packages" "c:\Python36\Lib\site-packages.pycache_copy"
  rem   3. mkdir "c:\Python36\Lib\site-packages.pycache_copy"
  rem      call copy_pycache.bat -prefix_dirs "" -suffix_names "" "c:\Python36\Lib\site-packages" "c:\Python36\Lib\site-packages.pycache_copy"
  rem
  
  setlocal
  