[report_py3o] errore in print pdf

[matteoopenf]

Module

report_py3o

Describe the bug

When I try to print a pdf from Libro Giornale
I obtain
File "/opt/odoo/community_addons/bundles/reporting-engine/report_py3o/controllers/main.py", line 69, in report_download
requestcontent = json.loads(data)
File "/usr/lib/python3.7/json/init.py", line 341, in loads
raise TypeError(f'the JSON object must be str, bytes or bytearray, '
TypeError: the JSON object must be str, bytes or bytearray, not generator

To Reproduce

Affected versions:

• 12.0

Steps to reproduce the behavior:

1. Print a libro giornale from this module https://github.com/OCA/l10n-italy/tree/12.0/l10n_it_central_journal
2. Obtain error

Expected behavior
the print works fine