The \help; command produces "token recognition error"

I'm using radb version 3.0.2 with Python 3.7.4 from Anaconda 3, on macOS Mojave 10.14.6.

When I run the \help; command at the ra> prompt, I get what appears to be a parsing error: ERROR: line 1:0 token recognition error at: '\h'. Here is the full context:

$ radb beers.db
WARNING: unable to read configuration file /Users/Foobar/.radb.ini; resorting to system defaults
radb: A relational algebra interpreter over relational databases
Version 3.0.2 by Jun Yang <junyang@cs.duke.edu>
https://github.com/junyang/radb
ra> \list;
database relations:
  Bar(name:string, address:string)
  Beer(name:string, brewer:string)
  Drinker(name:string, address:string)
  Frequents(drinker:string, bar:string, times_a_week:number)
  Likes(drinker:string, beer:string)
  Serves(bar:string, beer:string, price:number)
ra> \help;
ERROR: line 1:0 token recognition error at: '\h'
ra> \quit;
$

junyang / radb

The \help; command produces "token recognition error" #3