input: Write a python function to compute the sum of all the odd numbers between 1 and 1000.
  assert sum_odd_numbers(1000) == 250000
  assert sum_odd_numbers(10) == 25
  assert sum_odd_numbers(1) == 1
output: def sum_odd_numbers(n):
      return sum(i for i in range(1, n + 1) if i % 2 != 0)