public Group createGroup(String playerName){
  if (getGroup(playerName) != null) {
    return null;
  }
  Group group=new Group();
  group.addMember(playerName);
  groups.add(group);
  return group;
}

public Group createGroup ( String playerName ) { if ( getGroup ( playerName ) != null ) { return null ; } Group group = new Group ( ) ; group . addMember ( playerName ) ; groups . add ( group ) ; return group ; }
creates a new group
