Write a function that converts light$-$years to miles. Your function should take as input a numerical

value representing the number of light$-$years. Your function should then convert this value to miles, and

return the result as its output. It should also print the result of the conversion in the format shown below.

Your function should make sure that the input is nonnegative. If the input is negative, an error message

should be displayed, your output variable should be returned as Not a Number as shown in class, and your

function should return early. Examples of expected input and output:

$>ly2mi(1)$

$1$ light$-$year $=5879000000000mi.$

ans $=$

$5\mathrm{.}8790e+12$

$>ly2mi(5)$

$5$ light$-$year $=29395000000000mi.$

ans $=$

$2\mathrm{.}9395e+13$