You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: CCR.m
    path of file: ./repos/orca/src/Measures
    
    the code of the file until where you have to start completion: classdef CCR < Metric
    %CCR static class to calculate the correct classification rate or accuracy,
    % which is the percentage of c
    
function value = calculateCrossvalMetric(argum1,argum2)
            %CALCULATECROSSVALMETRIC Computes the evaluation metric and returns
            %it as an error.
            %   METRIC = CALCULATECROSSVALMETRIC(CM) returns calculated metric from confussion
            %   matrix CM
            %   METRIC = CALCULATECROSSVALMETRIC(actual, pred) returns calculated metric from
            %   real labels (ACTUAL) labels and predicted labels (PRED)
            if nargin == 2
                value = 1 - sum(argum1==argum2)/numel(argum1);
            else
                value = 1 - sum(diag(argum1)) / sum(sum(argum1));
            end