Group by Region

Let's build a new scatter plot with the same data, but this time painting the points with respect to the region (the 'continent' column). Follow the next steps:

1. Iterate over pair of colors and regions, using color and region as dummy variables.
2. Within the loop, filter the observations to a particular continent (respective value of region variable).
3. Then, within the same loop, initialize a scatter plot of 'gdp per capita' vs 'life exp'. Set color of points to color and set the label parameter to region.
4. Display the legend of the plot.