input: Write a function to optimize cost production.
  assert optimization([4], 1) == 1
  assert optimization([5, 3, 2], 2) == 6
  assert optimization([], 3) == 0
output: def optimization(production_costs, num_productions):
      if not production_costs or num_productions <= 0:
          return 0
      sorted_costs = sorted(production_costs)
      return sum(sorted_costs[:num_productions])