Function py_kopf_kmatrix_f2 

pub fn py_kopf_kmatrix_f2(
    tags: &Bound<'_, PyTuple>,
    couplings: [[PyParameter; 2]; 4],
    channel: PyKopfKMatrixF2Channel,
    mass: PyMass,
    seed: Option<usize>,
) -> PyResult<PyExpression>

Construct the fixed Kopf f2 K-matrix amplitude.