pub type Secp256k1Chip<'chip, F> = EccChip<'chip, F, FpChip<'chip, F>>;
struct Secp256k1Chip<'chip, F> { pub field_chip: &'chip FpChip<'chip, F, Fp>, /* private fields */ }
field_chip: &'chip FpChip<'chip, F, Fp>