docs: def set_avatar(self, asset_id):
          """Sets the avatar asset.
  
          arg:    asset_id (osid.id.Id): an asset ``Id``
          raise:  InvalidArgument - ``asset_id`` is invalid
          raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          # Implemented from template for osid.resource.ResourceForm.set_avatar_template
          if self.get_avatar_metadata().is_read_only():
              raise errors.NoAccess()
          if not self._is_valid_id(asset_id):
              raise errors.InvalidArgument()
          self._my_map['avatarId'] = str(asset_id)