Arguments for the EM that estimates ctwas's group priors.
Two callees, because the pipeline falls back from
ctwas::est_param() to ctwas's internal fit_EM() when the
accurate EM diverges; fit_EM() is not a subset of
est_param() (groups, types, contexts,
warn_converge_fail are its own), so the bundle is checked against
both and .ctwasInvoke() drops whichever the running step does not
take.
Value
A MethodOptions object.