computeModelsMeta = yPred => {
  const predInstance0 = yPred[0][0];
  const classLabels = Object.keys(predInstance0);
  const nClasses = classLabels.length > 1 ? classLabels.length : 1;
  return {
    nModels: yPred.length,
    nClasses,
    classLabels,
  };
}
compute basic information of models
@param {[Array]} yPred - An array of arrays, predicted values for each class from each models.
@return {Number} nModels
@return {Number} nClasses
@return {Array} classLabels - array of strings representing class names