code: def normalize_drive(path):
      
      if os.name != "nt" or not isinstance(path, six.string_types):
          return path
  
      drive, tail = os.path.splitdrive(path)
      # Only match (lower cased) local drives (e.g. 'c:'), not UNC mounts.
      if drive.islower() and len(drive) == 2 and drive[1] == ":":
          return "{}{}".format(drive.upper(), tail)
  
      return path
docs: Normalize drive in path so they stay consistent.
  
      This currently only affects local drives on Windows, which can be
      identified with either upper or lower cased drive names. The case is
      always converted to uppercase because it seems to be preferred.
  
      See: <https://github.com/pypa/pipenv/issues/1218>