Create a function that takes a list of numbers and returns the second largest number.
second_largest([10, 40, 30, 20, 50]) ➞ 40
second_largest([25, 143, 89, 13, 105]) ➞ 105
second_largest([54, 23, 11, 17, 10]) ➞ 23
There will be at least two numbers in the list.