new_contents: from mcpi import minecraft, block
  import time
  
  def flatWorld(mc, x, z):
      mc.setBlocks(-10 + x,-10,-10 + z,10 + x,0,10 + z, block.GRASS.id)
      mc.setBlocks(-10 + x,0,-10 + z,10 + x,35,10 + z, block.AIR.id)   
  
  mc = minecraft.Minecraft.create()
  for xVal in range(-7, 7):
      for zVal in range(-7, 7):
          flatWorld(mc, xVal*20,zVal *20)
          print "x: " + str(xVal) + " z: " + str(zVal)
          time.sleep(1)
  
subject: add script to flat a minecraft world