"""

"""
from __future__ import print_function
from __future__ import division
from __future__ import absolute_import


class Taggable(object):
  """
  Mixin trait for taggable objects.

  Currently not used.
  """
  pass


class TagService(object):
  """
  The tag service.
  """

  def tag(self, object, term, user=None):
    """Apply a tag on a taggable object.

    If user is None, uses the current logged in user.
    """

  def untag(self, object, term, user=None):
    """Remove the given tag from the given object. See tag().
    """

  def get_objects_tagged_with(self, term):
    """Returns a list of objects tagged with a given term.
    """

  def get_tags_applied_on(self, object):
    """Returns a list of tags applied on a given document.
    """
