How can Color Histogram perfomed on KNN to classify colors?

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General Topic: Color Matching Application by Feature Extraction with Classification

I decided to use "Color Histogram" and "K Nearest Neighbor" for classifying the colors.

I can get the image color histograms and I can deploy them in csv file with label to train KNN. This step is done! However, I can not figure out that how can send test image color histogram values to KNN for classifying it? There are a bunch of matrix values in test image color histogram. So my question is that how can send this point cloud (color histogram values of a test image) to KNN for classifying it?