`#[odra::external_contract]` should yield the trait itself.

[zie1ony]

I had to do something like this:

#[odra::external_contract]
pub trait Adapter {
    fn is_approved(&self, collection: Address, token_id: TokenId) -> bool;
    fn owner_of(&self, collection: Address, token_id: TokenId) -> Option<Address>;
    fn transfer_from(&mut self, collection: Address, from: Address, to: Address, token_id: TokenId);
}

pub trait Adapter {
    fn is_approved(&self, collection: Address, token_id: TokenId) -> bool;
    fn owner_of(&self, collection: Address, token_id: TokenId) -> Option<Address>;
    fn transfer_from(&mut self, collection: Address, from: Address, to: Address, token_id: TokenId);
}