ansible 2.10.5: ansible-vault requires either the cryptography library (preferred) or pycrypto in order to function

Good day! :)

After the last installation of Ansible on Ubuntu 20.04, an error occurs when launching ansible-vault:

-> % lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.1 LTS
Release:        20.04
Codename:       focal
-> % ansible --version  
ansible 2.10.5
  config file = /home/null/ansible-autoconnex/ansible.cfg
  configured module search path = ['/home/null/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/null/.local/lib/python3.9/site-packages/ansible
  executable location = /home/null/.local/bin/ansible
  python version = 3.9.0+ (default, Oct 20 2020, 08:43:38) [GCC 9.3.0]
-> % ansible-vault edit users.yml
ERROR! ansible-vault requires either the cryptography library (preferred) or pycrypto in order to function. for /home/null/ansible-autoconnex/users.yml  

The problem is the lack of cffi library. Most likely the developers forgot to specify the dependency somewhere. Just install cffi.

-> % pip install cffi