code: def get_root(self, drive):
          
          drive = _my_normcase(drive)
          try:
              return self.Root[drive]
          except KeyError:
              root = RootDir(drive, self)
              self.Root[drive] = root
              if not drive:
                  self.Root[self.defaultDrive] = root
              elif drive == self.defaultDrive:
                  self.Root[''] = root
              return root
docs: Returns the root directory for the specified drive, creating
          it if necessary.