docs: public static void sanitizeViews(Map<Address,View> map) {
          if(map == null)
              return;
          for(Map.Entry<Address,View> entry: map.entrySet()) {
              Address key=entry.getKey();
              List<Address> members=new ArrayList<>(entry.getValue().getMembers());
              boolean modified=false;
              for(Iterator<Address> it=members.iterator(); it.hasNext();) {
                  Address val=it.next();
                  if(val.equals(key)) // we can always talk to ourself !
                      continue;
                  View view=map.get(val);
                  final Collection<Address> tmp_mbrs=view != null? view.getMembers() : null;
                  if(tmp_mbrs != null && !tmp_mbrs.contains(key)) {
                      it.remove();
                      modified=true;
                  }
              }
              if(modified) {
                  View old_view=entry.getValue();
                  entry.setValue(new View(old_view.getViewId(), members));
              }
          }
      }