code: def odd_sum(a, b):
      # find first odd number
      if a % 2 == 0:
          a += 1
      # to avoid rounding (math.ceil) find the biggest even number
      if b % 2 == 1:
          b += 1
      # count of odd numbers
      n = (b - a + 1) // 2
      # use the formula from the description
      return n * (a + n - 1)
  
label_desc: Use image node_id 1 for calling a global function with example usage: odd_sum(a, b) and returns: unknown