old_contents: from __future__ import unicode_literals
  
  
  class Mixer(object):
      """Audio mixer API"""
  
      name = None
      """Name of the mixer.
  
      Used when configuring what mixer to use. Should match the
      :attr:`~mopidy.ext.Extension.ext_name` of the extension providing the
      mixer.
      """
  
      def get_volume(self):
          """
          Get volume level of the mixer.
  
          Example values:
  
          0:
              Minimum volume, usually silent.
          100:
              Max volume.
          :class:`None`:
              Volume is unknown.
  
          :rtype: int in range [0..100] or :class:`None`
          """
          return None
  
      def set_volume(self, volume):
          """
          Set volume level of the mixer.
  
          :param volume: Volume in the range [0..100]
          :type volume: int
          :rtype: :class:`True` if success, :class:`False` if failure
          """
          return False
  
      def get_mute(self):
          """
          Get mute status of the mixer.
  
          :rtype: :class:`True` if muted, :class:`False` if unmuted,
            :class:`None` if unknown.
          """
          return None
  
      def set_mute(self, muted):
          """
          Mute or unmute the mixer.
  
          :param muted: :class:`True` to mute, :class:`False` to unmute
          :type muted: bool
          :rtype: :class:`True` if success, :class:`False` if failure
          """
          return False
  
new_contents: from __future__ import unicode_literals
  
  
  class Mixer(object):
      """Audio mixer API"""
  
      name = None
      """Name of the mixer.
  
      Used when configuring what mixer to use. Should match the
      :attr:`~mopidy.ext.Extension.ext_name` of the extension providing the
      mixer.
      """
  
      def get_volume(self):
          """
          Get volume level of the mixer.
  
          Example values:
  
          0:
              Minimum volume, usually silent.
          100:
              Max volume.
          :class:`None`:
              Volume is unknown.
  
          *MAY be implemented by subclass.*
  
          :rtype: int in range [0..100] or :class:`None`
          """
          return None
  
      def set_volume(self, volume):
          """
          Set volume level of the mixer.
  
          *MAY be implemented by subclass.*
  
          :param volume: Volume in the range [0..100]
          :type volume: int
          :rtype: :class:`True` if success, :class:`False` if failure
          """
          return False
  
      def get_mute(self):
          """
          Get mute status of the mixer.
  
          *MAY be implemented by subclass.*
  
          :rtype: :class:`True` if muted, :class:`False` if unmuted,
            :class:`None` if unknown.
          """
          return None
  
      def set_mute(self, muted):
          """
          Mute or unmute the mixer.
  
          *MAY be implemented by subclass.*
  
          :param muted: :class:`True` to mute, :class:`False` to unmute
          :type muted: bool
          :rtype: :class:`True` if success, :class:`False` if failure
          """
          return False
  
subject: Mark methods that may be implemented by subclasses