temp.rs

    fn witness_script<ToPkCtx: Copy>(&self, to_pk_ctx: ToPkCtx) -> BtcScript
    where
        Pk: ToPublicKey<ToPkCtx>,
    {
        let tweak = self.desc.witness_script(to_pk_ctx).into_bytes();
      
        let mut builder = script::Builder::new()
            .push_opcode(opcodes::all::OP_DEPTH)
            .push_int(self.fed_k as i64 + 1)
            .push_opcode(opcodes::all::OP_EQUAL)
            .push_opcode(opcodes::all::OP_IF)
            .push_int(self.fed_k as i64);
        for key in &self.fed_pks {
            // Typing error here: 
            let tweaked_pk = key.to_public_key((to_pk_ctx, &tweak));
                                              //^^^^^^^^^^^^^^^^^^^ expected type parameter `ToPkCtx`, found tuple
            builder = builder.push_key(&tweaked_pk);
        }
}