Cannot EDIT any page in backend: Fatal Error: Undefined class constant 'DEFAULT_OPEN_TAG' (line 111 of site/modules/HannaCodeHelper/HannaCodeHelper.module)

[hollyvalero]

EDITING TO ADD FIX:  after comparing the two installations, one had Hannacodehelper still installed - so I deleted that and it's working just fine now.

 

I have a website with a lot of charts in Hanna Code snippets. When trying to edit pages, getting a big fatal error - which is new. When I installed this it was working fine, so something since then seems to have triggered it.

Fatal Error: Undefined class constant 'DEFAULT_OPEN_TAG' (line 111 of site/modules/HannaCodeHelper/HannaCodeHelper.module)

- everything is up to date
- PHP version is 7.3
- compiled files cleared
- cache cleared

Error log in PW says:
Fatal Error: Undefined class constant 'DEFAULT_OPEN_TAG'
Line 111 of /site/assets/cache/FileCompiler/site/modules/HannaCodeHelper/HannaCodeHelper.module

Referring to: 

// basic settings
        $data = $this->modules->getModuleConfigData('TextformatterHannaCode'); 
        $openTag = isset($data['openTag']) ? $data['openTag'] : \ProcessWire\TextformatterHannaCode::DEFAULT_OPEN_TAG;
        $closeTag = isset($data['closeTag']) ? $data['closeTag'] : \ProcessWire\TextformatterHannaCode::DEFAULT_CLOSE_TAG; 

Front end is working fine, and overall backend is accessible.

Any clues?