code: def touch(self, mode=0o666, exist_ok=True):
          
          if self._closed:
              self._raise_closed()
          if self.exists():
              if exist_ok:
                  self.filesystem.utime(self._path(), None)
              else:
                  self.filesystem.raise_os_error(errno.EEXIST, self._path())
          else:
              fake_file = self.open('w')
              fake_file.close()
              self.chmod(mode)
docs: Create a fake file for the path with the given access mode,
          if it doesn't exist.
  
          Args:
              mode: the file mode for the file if it does not exist
              exist_ok: if the file already exists and this is True, nothing
                  happens, otherwise FileExistError is raised
  
          Raises:
              OSError: (Python 2 only) if the file exists and exits_ok is False.
              FileExistsError: (Python 3 only) if the file exists and exits_ok is
                  False.