Deletes content from an ``Asset``.

        arg:    asset_content_id (osid.id.Id): the ``Id`` of the
                ``AssetContent``
        raise:  NotFound - ``asset_content_id`` is not found
        raise:  NullArgument - ``asset_content_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*

def delete_asset_content(self, asset_content_id):
        """Deletes content from an ``Asset``.

        arg:    asset_content_id (osid.id.Id): the ``Id`` of the
                ``AssetContent``
        raise:  NotFound - ``asset_content_id`` is not found
        raise:  NullArgument - ``asset_content_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*

        """
        # Implemented from template for
        # osid.repository.AssetAdminSession.delete_asset_content_template
        from dlkit.abstract_osid.id.primitives import Id as ABCId
        from .objects import AssetContent
        collection = JSONClientValidated('repository',
                                         collection='Asset',
                                         runtime=self._runtime)
        if not isinstance(asset_content_id, ABCId):
            raise errors.InvalidArgument('the argument is not a valid OSID Id')
        asset = collection.find_one({'assetContents._id': ObjectId(asset_content_id.get_identifier())})

        index = 0
        found = False
        for i in asset['assetContents']:
            if i['_id'] == ObjectId(asset_content_id.get_identifier()):
                asset_content_map = asset['assetContents'].pop(index)
            index += 1
            found = True
        if not found:
            raise errors.OperationFailed()
        AssetContent(
            osid_object_map=asset_content_map,
            runtime=self._runtime,
            proxy=self._proxy)._delete()
        collection.save(asset)