Get couriers

[url](../../docs/enum/additional_tracking_fields.md)[url](../../docs/enum/confidence_codes.md)[url](../../docs/enum/delivery_sub_statuses.md)[url](../../docs/enum/delivery_statuses.md)[url](../../docs/enum/slug_groups.md)[url](../../model/resource/tracking.json)[url](../../model/resource/checkpoint.json)[url](../../model/resource/courier.json)[url](../../model/resource/notification.json)[url](../../model/enum/additional_fields.v1.json)[url](../../model/enum/slug_group.v1.json)[url](../../model/enum/tag.v1.json)[url](../../reference/api.json/paths/~1trackings/get)[url](../../reference/api.json/paths/~1trackings/post)[url](../../reference/api.json/paths/~1trackings~1{slug}~1{tracking_number}/get)[url](../../reference/api.json/paths/~1trackings~1{slug}~1{tracking_number}/put)[url](../../reference/api.json/paths/~1trackings~1{slug}~1{tracking_number}/delete)[url](../../reference/api.json/paths/~1trackings~1{slug}~1{tracking_number}~1retrack/post)[url](../../reference/api.json/paths/~1trackings~1{slug}~1{tracking_number}~1mark-as-completed/post)[url](../../reference/api.json/paths/~1couriers/get)[url](../../reference/api.json/paths/~1couriers~1detect/post)[url](../../reference/api.json/paths/~1couriers~1all/get)[url](../../reference/api.json/paths/~1last_checkpoint~1{slug}~1{tracking_number}/get)[url](../../reference/api.json/paths/~1notifications~1{slug}~1{tracking_number}/get)[url](../../reference/api.json/paths/~1notifications~1{slug}~1{tracking_number}~1add/post)[url](../../reference/api.json/paths/~1notifications~1{slug}~1{tracking_number}~1remove/post)[url](../../docs/quickstart/authentication.md)