Moons-iMac:~ moon$ nix-env -i python3
warning: there are multiple derivations named 'python3-3.8.0b2'; using the first one
replacing old 'python3-3.7.2'
installing 'python3-3.8.0b2'
these derivations will be built:
  /nix/store/d0m49684nbb5klc3m3cmmidywnqkq0ar-python3-3.8.0b2.drv
building '/nix/store/d0m49684nbb5klc3m3cmmidywnqkq0ar-python3-3.8.0b2.drv'...
unpacking sources
unpacking source archive /nix/store/q3n3agifb1n9yrz0hrqa3ngw594g1rgs-Python-3.8.0b2.tar.xz
source root is Python-3.8.0b2
setting SOURCE_DATE_EPOCH to timestamp 1562241176 of file Python-3.8.0b2/Misc/NEWS
patching sources
applying patch /nix/store/gd8ycd6j3qhcq1qccaqz68zdq5l4c2wf-no-ldconfig.patch
patching file Lib/ctypes/util.py
applying patch /nix/store/9kwzs3pplms8sijf55sdryypzvic4x1s-python-3.x-distutils-C++.patch
patching file Lib/_osx_support.py
patching file Lib/distutils/cygwinccompiler.py
patching file Lib/distutils/sysconfig.py
Hunk #1 FAILED at 170.
Hunk #2 FAILED at 187.
Hunk #3 succeeded at 225 (offset 17 lines).
2 out of 3 hunks FAILED -- saving rejects to file Lib/distutils/sysconfig.py.rej
patching file Lib/distutils/unixccompiler.py
Hunk #3 FAILED at 183.
1 out of 3 hunks FAILED -- saving rejects to file Lib/distutils/unixccompiler.py.rej
patching file Makefile.pre.in
Hunk #1 succeeded at 601 (offset 17 lines).
builder for '/nix/store/d0m49684nbb5klc3m3cmmidywnqkq0ar-python3-3.8.0b2.drv' failed with exit code 1
error: build of '/nix/store/d0m49684nbb5klc3m3cmmidywnqkq0ar-python3-3.8.0b2.drv' failed