pip3 install cytoolz web3 : EOF ran out of input

Question

Working on Fedora 29, I want to install web3.py, using pip. In theory sudo pip3 install web3 works, but I get the following error:

ERROR: Complete output from command python setup.py egg_info:
ERROR: running egg_info
creating pip-egg-info/cytoolz.egg-info
writing pip-egg-info/cytoolz.egg-info/PKG-INFO
writing dependency_links to pip-egg-info/cytoolz.egg-info/dependency_links.txt
writing requirements to pip-egg-info/cytoolz.egg-info/requires.txt
writing top-level names to pip-egg-info/cytoolz.egg-info/top_level.txt
writing manifest file 'pip-egg-info/cytoolz.egg-info/SOURCES.txt'
Traceback (most recent call last):
[...]
File "/usr/lib64/python3.7/lib2to3/pgen2/grammar.py", line 108, in load
        d = pickle.load(f)
    EOFError: Ran out of input
    ----------------------------------------
ERROR: Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-req-build-rrup96_c/

Python3.7, pip3 up-to-date, setuptools up-to-date.

Since the error is generated during the installation of cytoolz, I tried to manually install it, first with pip3 install cytoolz, then by downloading the tar.gz from pypi.org, for the latest release (9.0.1.0) and the former (9.0.0). Tried reinstalling pip3, clearing the .cache/pip from /root and ~/. Always the same error.

As a side note, pip3 install requests works just fine.

Google has no clue about the EOFError with cytoolz. As suggested, it seems the error is thrown by pickle.load(f), so maybe it's trying to read a non-existing file. But the entire stack trace leaves me clueless about which file it could be. As I have tried to install several versions, I tend to think the missing file is not a cytoolz one.

I've been on this for many hours and exhausted by the lack of information. Any hint/solution would be greatly appreciated.