vdirsyncer failing with "ModuleNotFoundError: No module named 'atomicwrites"

I have just built vdirsyncer (a Python application) from SlackBuilds but when I try to run it I get:
Code:bash-5.1$ vdirsyncer showconfig
Traceback (most recent call last):
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/__init__.py", line 32, in inner
f(*a, **kw)
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/__init__.py", line 61, in app
from .config import load_config
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/config.py", line 14, in <module>
from .utils import storage_class_from_config
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/utils.py", line 10, in <module>
from atomicwrites import atomic_write
ModuleNotFoundError: No module named 'atomicwrites'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/bin/vdirsyncer", line 33, in <module>
sys.exit(load_entry_point('vdirsyncer==0.19.2', 'console_scripts', 'vdirsyncer')())
File "/usr/lib64/python3.9/site-packages/click/core.py", line 1157, in __call__
return self.main(*args, **kwargs)
File "/usr/lib64/python3.9/site-packages/click/core.py", line 1078, in main
rv = self.invoke(ctx)
File "/usr/lib64/python3.9/site-packages/click/core.py", line 1685, in invoke
super().invoke(ctx)
File "/usr/lib64/python3.9/site-packages/click/core.py", line 1434, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/lib64/python3.9/site-packages/click/core.py", line 783, in invoke
return __callback(*args, **kwargs)
File "/usr/lib64/python3.9/site-packages/click/decorators.py", line 92, in new_func
return ctx.invoke(f, obj, *args, **kwargs)
File "/usr/lib64/python3.9/site-packages/click/core.py", line 783, in invoke
return __callback(*args, **kwargs)
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/__init__.py", line 34, in inner
from .utils import handle_cli_error
File "/usr/lib64/python3.9/site-packages/vdirsyncer/cli/utils.py", line 10, in <module>
from atomicwrites import atomic_write
ModuleNotFoundError: No module named 'atomicwrites'I assume that this can be fixed by adding in python3-atomicwrites as a dependency, but I am not good with python.
Should I add python3-atomicwrites as a dependency of click, rebuild click and then rebuild vdirsyncer?