I downloaded the code from the github repo and made only two modifications, regarding the version of Bokeh installed in my system (1.1.0), so lines 5 and 6 of layout.html became

<link rel="stylesheet" href="http://cdn.pydata.org/bokeh/release/bokeh-1.1.0.min.css" type="text/css" />

<script type="text/javascript" src="http://cdn.pydata.org/bokeh/release/bokeh-1.1.0.min.js"></script>

However, when I run the script, the output of http://127.0.0.1:5000/dashboard is a blank page with the title Bokeh sample. I get no errors running the code, and the console output (with FLASK_ENV=development) is

 * Environment: development
 * Debug mode: on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 232-909-816
127.0.0.1 - - [17/Apr/2019 16:26:41] "GET / HTTP/1.1" 200 -
127.0.0.1 - - [17/Apr/2019 16:26:55] "GET /dashboard/ HTTP/1.1" 200 -

I am running this example on macOS Mojave (10.14.4), with python 3.6.8, bokeh 1.1.0 and flask 1.0.2. Can you help me get this code running?