Installation fails if running not under root

When running pip install as a normal user, installation fails trying to write /usr/include/lisaconstants.hpp:

Installing collected packages: lisaconstants
    Running setup.py install for lisaconstants: started
    Running setup.py install for lisaconstants: finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /usr/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-w6eq5y7k/setup.py'"'"'; __file__='"'"'/tmp/pip-req-build-w6eq5y7k/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-vk705qs1/install-record.txt --single-version-externally-managed --user --prefix= --compile --install-headers /home/testuser/.local/include/python3.8/lisaconstants
         cwd: /tmp/pip-req-build-w6eq5y7k/
    Complete output (32 lines):
    running install
    running build
    running build_py
    creating build
    creating build/lib
    creating build/lib/lisaconstants
    copying lisaconstants/__init__.py -> build/lib/lisaconstants
    copying lisaconstants/cheader.py -> build/lib/lisaconstants
    copying lisaconstants/constants.py -> build/lib/lisaconstants
    copying lisaconstants/meta.py -> build/lib/lisaconstants
    running install_lib
    creating /home/testuser/.local/lib/python3.8/site-packages/lisaconstants
    copying build/lib/lisaconstants/__init__.py -> /home/testuser/.local/lib/python3.8/site-packages/lisaconstants
    copying build/lib/lisaconstants/cheader.py -> /home/testuser/.local/lib/python3.8/site-packages/lisaconstants
    copying build/lib/lisaconstants/constants.py -> /home/testuser/.local/lib/python3.8/site-packages/lisaconstants
    copying build/lib/lisaconstants/meta.py -> /home/testuser/.local/lib/python3.8/site-packages/lisaconstants
    byte-compiling /home/testuser/.local/lib/python3.8/site-packages/lisaconstants/__init__.py to __init__.cpython-38.pyc
    byte-compiling /home/testuser/.local/lib/python3.8/site-packages/lisaconstants/cheader.py to cheader.cpython-38.pyc
    byte-compiling /home/testuser/.local/lib/python3.8/site-packages/lisaconstants/constants.py to constants.cpython-38.pyc
    byte-compiling /home/testuser/.local/lib/python3.8/site-packages/lisaconstants/meta.py to meta.cpython-38.pyc
    running install_egg_info
    running egg_info
    writing lisaconstants.egg-info/PKG-INFO
    writing dependency_links to lisaconstants.egg-info/dependency_links.txt
    writing top-level names to lisaconstants.egg-info/top_level.txt
    reading manifest file 'lisaconstants.egg-info/SOURCES.txt'
    writing manifest file 'lisaconstants.egg-info/SOURCES.txt'
    Copying lisaconstants.egg-info to /home/testuser/.local/lib/python3.8/site-packages/lisaconstants-1.0.egg-info
    running install_scripts
    writing list of installed files to '/tmp/pip-record-vk705qs1/install-record.txt'
    installing C++ header file -> /usr/include/lisaconstants.hpp
    error: [Errno 13] Permission denied: '/usr/include/lisaconstants.hpp'