Problem 2 Write a function gaussian that calculates the Gaussian pdf, f(0) = exp-}(*5")] . When called with only x as an input argument, the function should return the pdf of the standard Gaussian distribution. In [ ]: # Write the function here # YOUR CODE HERE raise Not ImplementedError() In [ ]: from nose. tools import assert_equal assert_equal(gaussian(1, 1.2, 2), 0.1984762737385059) assert_equal(gaussian(1), 0.24197072451914337)