PIL/Pillow test: crash converting transparent GIF to RGB

pil_test.py

import os.path
from PIL import Image

# image URLs for the two images used below:
# http://vectorpoem.com/images/grad.gif
# http://vectorpoem.com/images/grad2.gif

def convert_image(src_img_filename):
    # convert source image to RGB, then convert it to an arbitrary test palette
    print('reading %s...' % src_img_filename)
    out_img = Image.open(src_img_filename).convert('RGB')
    pal_img = Image.new('P', (1, 1))
    colors = [0, 0, 0, 128, 128, 128, 255, 0, 0]
    # PIL requires a tuple of exactly 768 integers for a palette :/
    while len(colors) < 768:
        colors += [0]
    pal_img.putpalette(tuple(colors))
    out_img = out_img.quantize(palette=pal_img)
    out_img = out_img.convert('RGB')
    print('conversion succeded')
    out_img.save('%s_out.png' % os.path.splitext(src_img_filename)[0])
    print('image written')

# test image 1: non-transparent non-animated GIF
convert_image('grad.gif')
# test image 2: transparent non-animated GIF
convert_image('grad2.gif')
#
# so why does image #1 crash but not image #2 ?!?
#

Program output on my machine:

[jpl@shada pil]$ python pil_test.py
reading grad.gif...
conversion succeded
image written
reading grad2.gif...
Traceback (most recent call last):
File "pil_test.py", line 23, in
convert_image('grad2.gif')
File "pil_test.py", line 16, in convert_image
out_img = out_img.convert('RGB')
File "/usr/lib/python3.4/site-packages/PIL/Image.py", line 890, in convert
trns_im.putpixel((0, 0), t)
File "/usr/lib/python3.4/site-packages/PIL/Image.py", line 1536, in putpixel
return self.im.putpixel(xy, value)
TypeError: an integer is required (got type tuple)

Fix for this is to remove transparency from the GIF before converting, eg
out_img.info['transparency'] = 0

Thanks @WoTToW!
The crash that happens in PIL could well be a bug; I should file it.