Write a function totret ( ) that calculates the total return of a NumPy array of returns. Assume the following: 1. Argument r is a NumPy array of decimal returns (i.e., r=0.1 indicates r=10% and r>100% for all r ) 2. Function totret() should return total return as a decimal Note: This question has 2 hidden tests worth a total of 20 points