input: Write a function to create a function in Python which takes a list as input and returns the sum of the items in the list.
  
  def sum_list(input_list):
    sum = 0
    for i in input_list:
      sum += i
    return sum
  
  assert sum_list([1, 2, 3, 4, 5])==15
  assert sum_list([10, 20, 30])==60
  assert sum_list([0, -1, 1])==0
  assert sum_list([])==0
  assert sum_list([-1, -2, -3])==-6
output: def sum_list(input_list):
    sum = 0
    for i in input_list:
      sum += i
    return sum