No virtualenv has been created for this project yet

[joedownloads1]

Hello i am having a problem with chomper:
i installed it with the help of a great guide here: https://chomper.readthedocs.io/en/latest/

Title is the beginning of a terminal response to my command:
chomper public 1440

the whole response:
No virtualenv has been created for this project yet!
File "/location/chomper/chomper/block.py", line 33 def main(rules_path: str, settings_json_path: str, rule: str,
^
SyntaxError: invalid syntax