$ pip3 install --user blspy==0.1.5
Collecting blspy==0.1.5
  Using cached https://files.pythonhosted.org/packages/1d/29/3bb073a1d4571989e6a88703cb7f28d39f73bf097d4402c3859edb9868cf/blspy-0.1.5.tar.gz
Building wheels for collected packages: blspy
  Running setup.py bdist_wheel for blspy ... error
  Failed building wheel for blspy
  Running setup.py clean for blspy
Failed to build blspy
Installing collected packages: blspy
  Running setup.py install for blspy ... error
Exception:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/pip/compat/__init__.py", line 73, in console_to_str
    return s.decode(sys.stdout.encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf3 in position 25: invalid continuation byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 360, in run
    prefix=options.prefix_path,
  File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/usr/lib/python3/dist-packages/pip/req/req_install.py", line 878, in install
    spinner=spinner,
  File "/usr/lib/python3/dist-packages/pip/utils/__init__.py", line 694, in call_subprocess
    line = console_to_str(proc.stdout.readline())
  File "/usr/lib/python3/dist-packages/pip/compat/__init__.py", line 75, in console_to_str
    return s.decode('utf_8')
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf3 in position 25: invalid continuation byte