TypeError in small keywords

[joswr1ght]

$ python3 gcpbucketbrute.py -u -k aa
Traceback (most recent call last):
  File "/Users/jwright/Dev/GCPBucketBrute.dist/gcpbucketbrute.py", line 237, in <module>
    main(args)
  File "/Users/jwright/Dev/GCPBucketBrute.dist/gcpbucketbrute.py", line 99, in main
    buckets = generate_bucket_permutations(args.keyword)
  File "/Users/jwright/Dev/GCPBucketBrute.dist/gcpbucketbrute.py", line 54, in generate_bucket_permutations
    del buckets[bucket]
TypeError: list indices must be integers or slices, not str
$ sed -n 52,56p gcpbucketbrute.py
    for bucket in buckets:
        if len(bucket) < 3 or len(bucket) > 63:
            del buckets[bucket]

    print(f'\nGenerated {len(buckets)} bucket permutations for keyword {keyword}.')

I've not used the built-in del for this operation before, but it doesn't work here.

$ python3 -V
Python 3.9.0