code: def is_unix_like(platform=None):
      
      platform = platform or sys.platform
      platform = platform.lower()
      return platform.startswith("linux") or platform.startswith("darwin") or \
              platform.startswith("cygwin")
docs: Returns whether the given platform is a Unix-like platform with the usual
      Unix filesystem. When the parameter is omitted, it defaults to ``sys.platform``