def __init__(self, drive):
"""
Creates a `DiskDrive` from a `drive`.
`drive` must be the path to a Windows disk drive (from 'A:' to 'Z:', case-insensitive).
If only the first positional argument is provided and it is already an instance of the
`DiskDrive` class (either directly or by inheritance), this constructor will clone
it and create a new `DiskDrive` object with the same properties.
"""
new_letter = drive._drive_letter if isinstance(drive, self.__class__) else drive
cleaned_letter = clean_drive_letter(new_letter)
if is_valid_drive_letter(cleaned_letter):
self._drive_letter = cleaned_letter
else:
raise InvalidDiskDriveError(new_letter)
def test_clean_drive_letter(self):
self.assertEqual(C.clean_drive_letter('A'), 'A')
self.assertEqual(C.clean_drive_letter('A:'), 'A')
self.assertEqual(C.clean_drive_letter('A:\\'), 'A')
self.assertEqual(C.clean_drive_letter('a'), 'A')
self.assertEqual(C.clean_drive_letter('a:\\'), 'A')
