input: Write a python function to sum all the numbers in a list using the reduce function from functools module.
  assert sum_list([1, 2, 3, 4]) == 10
  assert sum_list([10, 20, 30, 40]) == 100
  assert sum_list([5, 5, 5, 5]) == 20
output: from functools import reduce
  
  def sum_list(numbers):
      return reduce(lambda x, y: x + y, numbers)