Visualizing Cross-validation Code

Let's visualize to improve your prediction... Let us say, you are writing a nice and clean Machine Learning code (e.g. Your prediction could be slightly under or overfit, like the figures below. As the name of the suggests, cross-validation is the next fun thing after learning Linear Regression because it helps to improve your prediction using the K-Fold strategy. What is K-Fold you asked? Everything is explained below with Code.