def function SyntaxError: invalid syntax

[Said]

Hello, need help. I am trying to build a light spectrometer on a raspberry PI 3 from "http://blog.durablescope.com/post/BuiltASpectrometer/"

when i implement spectrometer.py file I get this message:
"File "spectrometer.py", line 42
def find_aperture(pic_pixels, pic_width: int, pic_height: int) -> object:
^
SyntaxError: invalid syntax"

here is part of code:

import sys
import math
import time
import picamera
from fractions import Fraction
from collections import OrderedDict
from PIL import Image, ImageDraw, ImageFile, ImageFont


# scan a column to determine top and bottom of area of lightness
def get_spectrum_y_bound(pix, x, middle_y, spectrum_threshold, spectrum_threshold_duration):
    c = 0
    spectrum_top = middle_y
    for y in range(middle_y, 0, -1):
        r, g, b = pix[x, y]
        brightness = r + g + b
        if brightness < spectrum_threshold:
            c = c + 1
            if c > spectrum_threshold_duration:
                break
        else:
            spectrum_top = y
            c = 0

    c = 0
    spectrum_bottom = middle_y
    for y in range(middle_y, middle_y * 2, 1):
        r, g, b = pix[x, y]
        brightness = r + g + b
        if brightness < spectrum_threshold:
            c = c + 1
            if c > spectrum_threshold_duration:
                break
        else:
            spectrum_bottom = y
            c = 0

    return spectrum_top, spectrum_bottom


# find aperture on right hand side of image along middle line
def find_aperture(pic_pixels, pic_width: int, pic_height: int) -> object:
    middle_x = int(pic_width / 2)
    middle_y = int(pic_height / 2)
    aperture_brightest = 0
    aperture_x = 0
    for x in range(middle_x, pic_width, 1):
        r, g, b = pic_pixels[x, middle_y]
        brightness = r + g + b
        if brightness > aperture_brightest:
            aperture_brightest = brightness
            aperture_x = x

    aperture_threshold = aperture_brightest * 0.9
    aperture_x1 = aperture_x
    for x in range(aperture_x, middle_x, -1):
        r, g, b = pic_pixels[x, middle_y]
        brightness = r + g + b
        if brightness < aperture_threshold:
            aperture_x1 = x
            break

    aperture_x2 = aperture_x
    for x in range(aperture_x, pic_width, 1):
        r, g, b = pic_pixels[x, middle_y]
        brightness = r + g + b
        if brightness < aperture_threshold:
            aperture_x2 = x
            break

    aperture_x = (aperture_x1 + aperture_x2) / 2

    spectrum_threshold_duration = 64
    aperture_y_bounds = get_spectrum_y_bound(pic_pixels, aperture_x, middle_y, aperture_threshold, spectrum_threshold_duration)
    aperture_y = (aperture_y_bounds[0] + aperture_y_bounds[1]) / 2
    aperture_height = (aperture_y_bounds[1] - aperture_y_bounds[0]) * 0.9

    return {'x': aperture_x, 'y': aperture_y, 'h': aperture_height, 'b': aperture_brightest}

Thank you

[Said]

Solved,
the problem was in the python version