Inverse replace

from pymclevel import MCSchematic
from pymclevel import TileEntity
from pymclevel import TAG_Compound
from pymclevel import TAG_Short
from pymclevel import TAG_Byte
from pymclevel import TAG_String
import random

displayName = "Inverse Replace"

inputs = (
    ("Fill with", "blocktype"),
    ("Leave", "blocktype"),
)

def perform(level, box, options):
    mat1 = options["Fill with"]
    mat2 = options["Leave"]
    for (chunk, slices, point) in level.getChunkSlices(box):
        blocks = chunk.Blocks[slices]
        blocks[blocks != mat2.ID] = mat1.ID
        chunk.chunkChanged()
def randomGen():
    return int(random.random() * 99) + 1