code: def wherex_to_rowlist(scope_, fromx, wherex):
    
    single, multi = classify_wherex(scope_, fromx, wherex)
    single_rowlists = {
      tablename: table_to_rowlist(scope_[tablename], conds)
      for tablename, conds in misc.multimap(single).items() # i.e. {cond.table:[cond.exp, ...]}
    }
    raise NotImplementedError
docs: return a RowList with the rows included from scope by the fromx and wherex.
    When the scope has more than one name in it, the output will be a list of composite row
      (i.e. a row whose field types are themselves RowType).