@staticmethod
def load_exactly_one_document(_collection, _id, _zero_error=None,
    _duplicate_error=None):
    """
        Raises provided errors if not exactly one row in result.

        :param _collection: The collection to load from
        :param _id: The _id of the document
        :param _zero_error: Error to report if no documents are found
        :param _duplicate_error: Error to report when duplicate documents are found
        :return: The document
        """
    _document_cursor = _collection.find({'_id': _id})
    if _document_cursor.count() == 0:
        if _zero_error is not None:
            raise Exception(_zero_error + '_id: ' + str(_id) +
                ' could not be found.')
        else:
            return None
    elif _document_cursor.count() > 1:
        if _duplicate_error is not None:
            raise Exception(
                'Access.save: Tried saving existing, but found duplicate documents with(try to remove either) _id: '
                 + str(_id) + '.')
        else:
            return None
    elif _document_cursor.count() == 1:
        return _document_cursor[0]
