Why Am Getting ModuleNotFoundError: No module named 'memcache' Error During an Ansible Tower Version Upgrade?

Issue

• During an upgrade of Ansible Tower, the following error occurs:

  TASK [preflight : Preflight check - check Tower license type] 
  fatal: [tower.example.com]: FAILED! => {"changed": true, "cmd": "awx-manage check_license", "delta": 
  "0:00:03.793918", "end":
  ...
  import memcache", "ModuleNotFoundError: No module named 'memcache'"], "stdout": "", "stdout_lines": []}