Specify selection criteria for bulk operations.

        :Parameters:
          - `selector` (dict): the selection criteria for update
            and remove operations.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only
            supported on MongoDB 3.4 and above.

        :Returns:
          - A :class:`BulkWriteOperation` instance, used to add
            update and remove operations to this bulk operation.

        .. versionchanged:: 3.4
           Added the `collation` option.

def find(self, selector, collation=None):
        """Specify selection criteria for bulk operations.

        :Parameters:
          - `selector` (dict): the selection criteria for update
            and remove operations.
          - `collation` (optional): An instance of
            :class:`~pymongo.collation.Collation`. This option is only
            supported on MongoDB 3.4 and above.

        :Returns:
          - A :class:`BulkWriteOperation` instance, used to add
            update and remove operations to this bulk operation.

        .. versionchanged:: 3.4
           Added the `collation` option.

        """
        validate_is_mapping("selector", selector)
        return BulkWriteOperation(selector, self.__bulk, collation)