error: expected literal
 --> $DIR/string-literal.rs:6:22
  |
6 |     #[guzzle(keys = [one, two])]
  |                      ^^^

error[E0599]: no method named `guzzle` found for type `GuzzleExample` in the current scope
  --> $DIR/string-literal.rs:23:40
   |
4  | struct GuzzleExample {
   | -------------------- method `guzzle` not found for this
...
23 |         .filter_map(|v| guzzle_example.guzzle(v))
   |                                        ^^^^^^ method not found in `GuzzleExample`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `guzzle`, perhaps you need to implement it:
           candidate #1: `guzzle::Guzzle`