pub fn ec_select_from_bits<F: PrimeField, FC, Pt>(
    chip: &FC,
    ctx: &mut Context<F>,
    points: &[Pt],
    sel: &[AssignedValue<F>]
) -> EcPoint<F, FC::FieldPoint>where
    FC: FieldChip<F> + Selectable<F, FC::FieldPoint>,
    Pt: Into<EcPoint<F, FC::FieldPoint>> + Clone,