code: func addContext(db *sqlx.DB, in *dt.Msg) error {
  	if len(in.StructuredInput.Times) == 0 {
  		if err := addTimeContext(db, in); err != nil {
  			return err
  		}
  	}
  	if len(in.StructuredInput.People) == 0 {
  		if err := addPeopleContext(db, in); err != nil {
  			return err
  		}
  	}
  	return nil
  }
docs: // addContext to a Msg, filling in pronouns with the terms to which they refer.
  // The sentence/stems/tokens are left unmodified; addContext simply appends the
  // contextual terms to the StructuredInput when it's otherwise empty.