input: Write a python function to find the second largest number from a given list.
  assert second_largest_number([12, 23, 45, 22, 50]) == 45
  assert second_largest_number([10, 15, 20, 25, 30]) == 25
  assert second_largest_number([1, 2, 3, 4, 5]) == 4
output: def second_largest_number(numbers):
      first = second = float('-inf')
      for n in numbers:
          if n > first:
              second = first
              first = n
          elif n > second and n != first:
              second = n
      return second