The variable {{ clickhouse_repo_old }} is not defined

[free6k]

Debian stretch have problems ... on file line

https://github.com/AlexeySetevoi/ansible-clickhouse/blob/master/tasks/install_apt.yml#L12

The variable {{ clickhouse_repo_old }} is not defined

fatal: [55.55.55.5]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'clickhouse_repo_old' is undefined\n\nThe error appears to have been in '/etc/ansible/roles/alexeysetevoi.clickhouse/tasks/install_apt.yml': line 10, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Install by APT | Remove old repo link of exists\n  ^ here\n\nexception type: <class 'ansible.errors.AnsibleUndefinedVariable'>\nexception: 'clickhouse_repo_old' is undefined"}