Installization failed. PyPI package is not registered

[execut]

Hello! Why is the package missing?

$ pip install cmsplugin-gridloading
ERROR: Could not find a version that satisfies the requirement cmsplugin-gridloading (from versions: none)
ERROR: No matching distribution found for cmsplugin-gridloading

[execut]

Temporarily installed via git, but here is the following problem:
$ ./manage.py migrate

Traceback (most recent call last):
 ModuleNotFoundError: No module named 'djangocms_attributes_field'

ok i install the package djangocms_attributes_field and again the problem occurs:

$ ./manage.py migrate
lib/python3.8/site-packages/cmsplugin_gridloading/utils.py", line 11, in get_additional_effects
    if isinstance(raw, basestring):
NameError: name 'basestring' is not defined