Running gilbert with no arguments causes a traceback

[shuttle1987]

$ gilbert 
Searching /Users/janis/BuzzwordsGlossary/venv/lib/python3.7/site-packages/gilbert/plugins for plugins...
Loaded plugin: yaml
Loaded plugin: markdown
Loaded plugin: scss
Loaded plugin: collection
Traceback (most recent call last):
  File "/Users/janis/BuzzwordsGlossary/venv/bin/gilbert", line 11, in <module>
    load_entry_point('gilbert==0.3.3', 'console_scripts', 'gilbert')()
  File "/Users/janis/BuzzwordsGlossary/venv/lib/python3.7/site-packages/gilbert/cli.py", line 95, in main
    args.func(args, site)
AttributeError: 'Namespace' object has no attribute 'func'