rules:
- id: use-count-method
  message: Looks like you need to determine the number of records. Django provides the count() method which is more efficient
    than .len(). See https://docs.djangoproject.com/en/3.0/ref/models/querysets/
  languages: [python]
  severity: ERROR
  pattern-either:
  - pattern: $X.objects.$FUNC(...).len()
  - pattern: $X.objects.$FUNC(...).$FILTER().len()
  - pattern: $X.objects.$FUNC(...).$FILTER().$UPDATE(...).len()
  metadata:
    category: performance
    technology:
    - django