Python imagehash doesn't play well with threadpoolexecutor

import time
from PIL import Image
import imagehash
import hashlib
import concurrent.futures
import numpy
import os

class ImageHasher:
    def __init__(self):
        print("__init__")
        pass

    def computeHash(self, image, hashFunction, hashSize):
        try:
            return hashFunction(image, hashSize)
        except:
            return None
        
    def compute_md5_hash(self, filename):
        with open(filename, "rb") as file:
            content = file.read()
            hash_object = hashlib.md5(content)
            return hash_object.hexdigest()

    def hashImage(self, imagePath):
        ret = {}
        try:
            with concurrent.futures.ThreadPoolExecutor() as executor:
                with Image.open(imagePath) as image:
                    # Submit the tasks to the executor
                    future_dhash10 = executor.submit(self.computeHash, image, imagehash.dhash, 10)
                    future_averageHash10 = executor.submit(self.computeHash, image, imagehash.average_hash, 10)
                    future_phash10 = executor.submit(self.computeHash, image, imagehash.phash, 10)
                    future_whash16 = executor.submit(self.computeHash, image, imagehash.whash, 16)
                    future_phashSimple8 = executor.submit(self.computeHash, image, imagehash.phash_simple, 8)
                    future_md5 = executor.submit(self.compute_md5_hash, imagePath)

                    # Wait for all tasks to complete
                    concurrent.futures.wait(
                        [future_dhash10, future_averageHash10, future_phash10, future_whash16, future_phashSimple8, future_md5]
                    )

                    # Store the results in the dictionary
                    ret["dhash10"] = future_dhash10.result()
                    ret["averageHash10"] = future_averageHash10.result()
                    ret["phash10"] = future_phash10.result()
                    ret["whash16"] = future_whash16.result()
                    ret["phashSimple8"] = future_phashSimple8.result()
                    ret["md5"] = future_md5.result()
        except Exception as e:
            print(f"Uh oh!! {e}")
        return ret
    
    def processImage(self):
        result = self.hashImage('result_image.jpg')
        count = 0
        # repeat until something fails.
        while result["dhash10"] != None and result["averageHash10"] != None and result["phash10"] != None and result["whash16"] != None  and result["phashSimple8"] != None and result["md5"] != None:
            result = self.hashImage('result_image.jpg')
            count+=1
        print("count: " + str(count))
        # print keys with missing value
        self.print_keys_with_none_values(result)
        return result
    
    def print_keys_with_none_values(self, dictionary):
        print("The following key(s) are None:")
        for key, value in dictionary.items():
            if value is None:
                print(key)

if __name__ == '__main__':
    # generate test data
    if not os.path.exists('result_image.jpg'):
        imarray = numpy.random.rand(3000, 4000,3) * 255
        im = Image.fromarray(imarray.astype('uint8')).convert('RGB')
        im.save('result_image.jpg',quality=95)
    ih = ImageHasher()
    start_time = time.time()
    result = ih.processImage()
    end_time = time.time()
    print("Time taken:", end_time - start_time)
    #print(result)