py3-cryptography: ModuleNotFoundError: No module named '_cffi_backend'
File "/usr/lib/python3.9/site-packages/cryptography/fernet.py", line 18, in <module>
from cryptography.hazmat.primitives import hashes, padding
File "/usr/lib/python3.9/site-packages/cryptography/hazmat/primitives/padding.py", line 13, in <module>
from cryptography.hazmat.bindings._padding import lib
ModuleNotFoundError: No module named '_cffi_backend'