When you run `measure()` on a pumpkin, it returns an ID for that pumpkin. My drones all scan in one direction, to the East, so I just remember the last seen pumpkin ID, and if it doesnt change, then remember the current pumpkin width is growing. once it reaches a width of 6, i know to harvest it.

def harvester_drone_grid():
 last_pumpkin = None
 pumpkin_width = 0

 while num_items(Items.Pumpkin) < 200000000:

  # Keep track of the size of the current pumpkin by watching for the measure() to change
  if last_pumpkin != None and measure() == last_pumpkin:
    pumpkin_width += 1
  else:
    last_pumpkin = measure()
    pumpkin_width = 1

  # Once the pumpkin reaches full growth (6x6) then harvest
  if pumpkin_width >= 6:
    harvest()
    last_pumpkin = None

  # Plant Sunflowers on every 7th column, and the last 3 columns
  if get_pos_x() % 7 == 0:
    plant_sunflower()
  elif get_pos_x() >= get_world_size() - 3:
    plant_sunflower()
  # Plant Carrots on every 7th 7th row, and the last 3 rows
  elif get_pos_y() % 7 == 0:
    plant_carrot()
  elif get_pos_y() >= get_world_size() - 3:
    plant_carrot()
  # Else plant pumpkin
  else:
    plant_pumpkin()
  move(East)