code: def find_executable(executable, path=None):
      
      if sys.platform != 'win32':
          return distutils.spawn.find_executable(executable, path)
  
      if path is None:
          path = os.environ['PATH']
  
      paths = path.split(os.pathsep)
      extensions = os.environ.get('PATHEXT', '.exe').split(os.pathsep)
      base, ext = os.path.splitext(executable)
  
      if not os.path.isfile(executable):
          for p in paths:
              for ext in extensions:
                  f = os.path.join(p, base + ext)
                  if os.path.isfile(f):
                      return f
          return None
      else:
          return executable
docs: As distutils.spawn.find_executable, but on Windows, look up
      every extension declared in PATHEXT instead of just `.exe`