new_contents: # fstask.py
  # Superclass for filesystem tasks.
  #
  # Copyright (C) 2015  Red Hat, Inc.
  #
  # This copyrighted material is made available to anyone wishing to use,
  # modify, copy, or redistribute it subject to the terms and conditions of
  # the GNU General Public License v.2, or (at your option) any later version.
  # This program is distributed in the hope that it will be useful, but WITHOUT
  # ANY WARRANTY expressed or implied, including the implied warranties of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  # Public License for more details.  You should have received a copy of the
  # GNU General Public License along with this program; if not, write to the
  # Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  # 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
  # source code or documentation are not subject to the GNU General Public
  # License and may only be used or replicated with the express permission of
  # Red Hat, Inc.
  #
  # Red Hat Author(s): Anne Mulhern <amulhern@redhat.com>
  
  import abc
  
  from six import add_metaclass
  
  from . import task
  
  @add_metaclass(abc.ABCMeta)
  class FSTask(task.Task):
      """ An abstract class that encapsulates the fact that all FSTasks
          have a single master object: the filesystem that they belong to.
      """
      description = "parent of all filesystem tasks"
  
      def __init__(self, an_fs):
          """ Initializer.
  
              :param FS an_fs: a filesystem object
          """
          self.fs = an_fs
  
  class UnimplementedFSTask(FSTask, task.UnimplementedTask):
      """ A convenience class for unimplemented filesystem tasks.
          Useful in the usual case where an Unimplemented task has
          no special methods that it is required to implement.
      """
      pass
  
subject: Add an abstract parent of all filesystem tasks.