`pycg` uses a lot of memory to create a Call Graph for specific packages

[amphioxis]

Hey @gdrosos and @vitsalis ,

running the pypi-plugin which uses pycg internally, for the packages click:7.0 and py:1.11.0, the process of creating a Call Graph uses all my memory (16 GB) and all my swap space (30 GB) without creating a Call Graph, while for other packages it only consumes a tiny fraction of that.

Not sure how to explain that better, so let me know which further information you need.

Thx for your help!

Additional packages: pyrsistent:0.18.1 Django:1.11.29 rjsmin:1.2.0 pyinotify:0.9.6 pytest:3.2.5 tqdm:4.64.0