Thanks that helped

Maybe a followup on GIF Animation via scripting.
I tried a very simple setup with the python script:
png file is loaded as image
pdb.script_fu_waves_anim(image, image.active_layer, 30, 35, 10, 0)
image = pdb.plug_in_animationoptimize(image, image.active_layer)
pdb.gimp_image_convert_indexed(image, 0, 0, 255, 0, 1, '')
pdb.file_gif_save(image, image.active_layer, '1.gif', '1.gif', 0, 1, 10, 1)
while str write is declared as a string specific string
Is there an apparent reason, why the .gif file is returning empty/ with 0 bytes?