Hi! If I am correct the Table group_by() object only supports .aggregate() method, which is only compatible with simple lambda-type functions (like numpy.mean, etc, taking in 1D arrays, returning a scalar). Are there plans to incorporate an equivalent of pandas groupby.apply(func), where func can perform any operations on the group, eg. using only specific columns, or performing arithmetic between different columns (eg. given a list of photometry grouped by object, with flux and flux_err columns calculate chi2 and weighted mean) ?