// Create data process pipeline
// First we have to change label value into ML.NET KeyType
var dataProcessPipeline = context.Transforms.Conversion.MapValueToKey("Label")
    // Then, we have to normalize text
    .Append(context.Transforms.Text.NormalizeText("Sentence", "NormalizedSentence"))
    // Featurize the given text with n-grams
    .Append(context.Transforms.Text.FeaturizeText("NormalizedSentence", "Features"))
    // Give the naive bayes algorithm
    .Append(context.MulticlassClassification.Trainers.NaiveBayes())
    // Convert back the label value to it's origin
    .Append(context.Transforms.Conversion.MapKeyToValue("PredictedLabel"));