Options forwarded to mashr::mash_estimate_corr_em, the
method = "mle" estimator.
data, Ulist and max_iter are refused: the first
two are what pecotmr assembles, and max_iter is the caller's
maxIter.
Not checkable: mash_estimate_corr_em ends in ..., so any
name is legal there and nothing can be rejected.
Value
A MethodOptions object.