@Nullable
    public static String extractErrorMessage(final BsonDocument response) {
        if (response.isString("err")) {
            return response.getString("err").getValue();
        } else if (response.isString("errmsg")) {
            return response.getString("errmsg").getValue();
        } else {
            return null;
        }
    }
@Nullable
    public static String extractErrorMessage(final BsonDocument response) {
        if (response.isString("err")) {
            return response.getString("err").getValue();
        } else if (response.isString("errmsg")) {
            return response.getString("errmsg").getValue();
        } else {
            return null;
        }
    }
@ Nullable public static String extractErrorMessage ( final BsonDocument response ) { if ( response . isString ( "err" ) ) { return response . getString ( "err" ) . getValue ( ) ; } else if ( response . isString ( "errmsg" ) ) { return response . getString ( "errmsg" ) . getValue ( ) ; } else { return null ; } }
For internal use only: extract the error message from the response to a write command.

@param response the response
@return the error message
For internal use only : extract the error message from the response to a write command .