input: Write a function to improve the given function by using Python built-in functions. The given function takes in an array of numbers and returns the sum of all the numbers.
  def sum_array(array):
      '''A function that takes in an array of numbers and returns the sum of all the numbers'''
      return sum(array)
  assert sum_array([1, 2, 3, 4, 5])==15
  assert sum_array([10, 20, 30])==60
  assert sum_array([])==0
output: def sum_array(array):
      return sum(array)