input: Write a python function to calculate the sum, average, maximum, and minimum of a list of numbers.
  assert calculate_list_metrics([-2, -4, 0, 5, 10]) == {'sum': 9, 'average': 1.8, 'max': 10, 'min': -4}
  assert calculate_list_metrics([1, 2, 3, 4, 5]) == {'sum': 15, 'average': 3.0, 'max': 5, 'min': 1}
  assert calculate_list_metrics([10, 20, 30, 40, 50]) == {'sum': 150, 'average': 30.0, 'max': 50, 'min': 10}
output: def calculate_list_metrics(numbers):
      total_sum = sum(numbers)
      average = total_sum / len(numbers)
      maximum = max(numbers)
      minimum = min(numbers)
      return {'sum': total_sum, 'average': average, 'max': maximum, 'min': minimum}