code: def get_annotation(component, db_name, db_ref):
      
      url = get_identifiers_url(db_name, db_ref)
      if not url:
          return None
      subj = component
      ann = Annotation(subj, url, 'is')
      return ann
docs: Construct model Annotations for each component.
  
      Annotation formats follow guidelines at http://identifiers.org/.