$ python3
Python 3.7.3 (default, Apr  3 2019, 05:39:12)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import his
>>> dir(his)
['ACCOUNT', 'Account', 'Application', 'CUSTOMER', 'JSON_DATA', 'SESSION', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', 'admin', 'api', 'application', 'authenticated', 'authorized', 'config', 'contextlocals', 'exceptions', 'functions', 'messages', 'orm', 'pwmail', 'root']
>>>

[uwsgi]
master = true
emperor = /etc/uwsgi-emperor/vassals
emperor-on-demand-directory = /run/uwsgi
plugin = python35
master = true
vassal-set = plugin=python3
vassal-set = master=true
vassal-set = enable-threads=false
vassal-set = cheaper-algo=spare
vassal-set = cheaper=1
vassal-set = cheaper-initial=1
vassal-set = cheaper-step=1
vassal-set = workers=8
vassal-set = enable-metrics=1

[uwsgi]
uid = his
gid = his
module = his.wsgi
callable = APPLICATION
buffer-size = 40960

*** Starting uWSGI 2.0.14-debian (64bit) on [Thu Apr 25 11:08:25 2019] ***
compiled with version: 6.3.0 20170516 on 17 March 2018 15:41:47
os: Linux-4.9.0-8-amd64 #1 SMP Debian 4.9.144-3 (2019-02-02)
nodename: srv
machine: x86_64
clock source: unix
pcre jit disabled
detected number of CPU cores: 8
current working directory: /etc/uwsgi-emperor/vassals
detected binary path: /usr/bin/uwsgi-core
setgid() to 963
setuid() to 963
your processes number limit is 64114
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
thunder lock: disabled (you can enable it with --thunder-lock)
uwsgi socket 0 inherited UNIX address /run/uwsgi/his.socket fd 0
Python version: 3.5.3 (default, Sep 27 2018, 17:25:39)  [GCC 6.3.0 20170516]
*** Python threads support is disabled. You can enable it with --enable-threads ***
Python main interpreter initialized at 0x562ddd200820
your server socket listen backlog is limited to 100 connections
your mercy for graceful operations on workers is 60 seconds
mapped 986688 bytes (963 KB) for 8 cores
*** Operational MODE: preforking ***
initialized 140 metrics
ImportError: No module named 'his'
unable to load app 0 (mountpoint='') (callable not found or import error)
*** no app loaded. going in full dynamic mode ***
*** uWSGI is running in multiple interpreter mode ***

$ dpkg -l | grep uwsgi-plugin-python3
ii  uwsgi-plugin-python3               2.0.14+20161117-3+deb9u2           amd64        WSGI plugin for uWSGI (Python 3)