'The number of documents modified.
.. note:: modified_count is only reported by MongoDB 2.6 and later.
When connected to an earlier server version, or in certain mixed
version sharding configurations, this attribute will be set to
``None``.'

@property
def modified_count(self):

    self._raise_if_unacknowledged('modified_count')
    return self.__bulk_api_result.get('nModified')
