[Python] Gaussian notch filter in Python

I'm trying to design a Gaussian notch filter in Python to remove periodic noise.I tried implementing the following formula:

Gaussian Notch Filter

And here is the code:

import numpy as np

def gaussian_bandpass_filter(image):
image_array = np.array(image)
#Fourier Transform
fourier_transform = np.fft.fftshift(np.fft.fft2(image_array))

#Size of Image
m = np.shape(fourier_transform)[0]
n = np.shape(fourier_transform)[1]

u = np.arange(m)
v = np.arange(n)

# Find the center
u0 = int(m/2)
v0 = int(n/2)

# Bandwidth
D0 = 10

gaussian_filter = np.zeros(np.shape(fourier_transform))

for x in u:
for y in v:
D1 = math.sqrt((x-m/2-u0)**2 + (y-n/2-v0)**2)
D2 = math.sqrt((x-m/2+u0)**2 + (y-n/2+v0)**2)
gaussian_filter[x][y] = 1 - math.exp(-0.5 * D1*D2/(D0**2))

#Apply the filter
fourier_transform = fourier_transform + gaussian_filter
image_array = np.fft.ifft2(np.fft.ifftshift(fourier_transform))

return image_array


this function is supposed to apply the Gaussian notch filter to an image and return the filtered image but it doesn't seem to work. I don't know where I went wrong with this (maybe I didn't understand the formula correctly?) so if anyone could help me I would really appreciate it.

Edit:

As an example, here is a noisy image. Using the existing gaussian_filter function in scipy.ndimage library, I get this, which is acceptable. But my function returns this. (I'm using PIL.Image.fromarray function to convert array to image)

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