Hi, wondering if pymatgen does any lexicographic ordering of Structure sites in addition to sorting by electronegativity, e.g. sorting Wyckoff sites.
Seems that get_sorted_structure() supports passing a callable. Will probably end up using or modifying this 
since the callable must take a single argument. I.e. the lexicographic aspect would need to either be a modification to the fn or embedded into the callable. Will post back once implemented.