/usr/lib/x86_64-linux-gnu/libpython3.7m.a is in libpython3.7-dev 3.7.0~b3-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/../python3.7/config-3.7m-x86_64-linux-gnu/libpython3.7m.a