Cannot render_to_file in pygal more than once in Spyder

问题

Short version
When in Spyder, if I run a script more than once that saves a map with pygal's render_to_file, I get a TypeError. It works fine the first time.

Detailed version
I'm trying to save a map using pygal (2.4.0) in Python 3.6 as follows:

from pygal.maps.world import World

worldmap = World()
worldmap.add('Random Places', ['mx', 'bz', 'ru', 'th', 'et'])
worldmap.render_to_file('random_places.svg')

It works fine when I run from the terminal as many times as I want (I'm on Ubuntu). It also works fine when I run it the first time from Spyder (3.2), using F5. Strangely, when I then try to run the code again in Spyder, after it has already run once and worked, the last line throws a TypeError. It creates an empty file random_places.svg, but stops there.

It will only run without error again if I restart the kernel (Consoles -> Restart kernel). Note also, if I run the above script, but add a second call to render_to_file, it also works fine (so it isn't as if the first call is somehow corrupting things).

Here is the traceback:

  File "/home/neuronet/SO_pygal_spyder", line 21, in <module>
    worldmap.render_to_file('random_places.svg')

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/graph/public.py", line 114, in render_to_file
    f.write(self.render(is_unicode=True, **kwargs))

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/graph/public.py", line 52, in render
    self.setup(**kwargs)

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/graph/base.py", line 185, in setup
    self.state = State(self, **kwargs)

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/state.py", line 35, in __init__
    merge(self.__dict__, graph.config.__class__.__dict__)

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/util.py", line 384, in merge
    dict1[key] = mergextend(val, dict1.get(key, ()))

  File "/home/neuronet/.local/lib/python3.6/site-packages/pygal/util.py", line 370, in mergextend
    if list1 is None or _ellipsis not in list1:

TypeError: argument of type 'Key' is not iterable

Related questions

Pygal Maps World Not Working
Error in Pygal :"render_to_file"

来源：https://stackoverflow.com/questions/45419033/cannot-render-to-file-in-pygal-more-than-once-in-spyder

标签

python

Anaconda

spyder

pygal