code: def xoscmounts(host_mount):
      
      callback_lower_drive_letter = lambda pat: pat.group(1).lower()
      host_mount = re.sub(r"^([a-zA-Z])\:", callback_lower_drive_letter, host_mount)
      host_mount = re.sub(r"^([a-z])", "//\\1", host_mount)
      host_mount = re.sub(r"\\", "/", host_mount)
      return host_mount
docs: Cross OS compatible mount dirs