Part 4 Implement a gradient descent function for linear regression: Wat was (w/x-Mix) The function will take trainData (RDD of LabeledPoint) as an argument and return a tuple of weights and

training errors. Reuse the code that you have written in Part 1 and 2. Initialize the elements of vector w = 0 and a = 1. Update the value of a in th iteration using the formula: Test the function on and example RDD. Run it for 5 iterations and print the results.