unpack_bootimg: TypeError: 'float' object cannot be interpreted as an integer

Package: mkbootimg
Version: 1:10.0.0+r36-7
Ubuntu: Impish

Unpacking an Android boot image results in an error:

$ unpack_bootimg --boot_img akernel
boot_magic: b'ANDROID!'
<snip />
Traceback (most recent call last):
  File "/usr/bin/unpack_bootimg", line 153, in <module>
    main()
  File "/usr/bin/unpack_bootimg", line 149, in main
    unpack_bootimage(args)
  File "/usr/bin/unpack_bootimg", line 127, in unpack_bootimage
    extract_image(image_info[0], image_info[1], args.boot_img,
  File "/usr/bin/unpack_bootimg", line 35, in extract_image
    bootimage.seek(offset)
TypeError: 'float' object cannot be interpreted as an integer

unpack_bootimg.py of https://android.googlesource.com/platform/system/tools/mkbootimg (tag: android-s-v2-preview-1) does not show the problem.