The m_widgets private member, which maps widget-type to wiget object,

The m_widgets private member, which maps widget-type to wiget object,
now maps to an array of widgets of that type. For most types of
widget, only one instance per team makes sense, so the team.widget
method now complains loudly if it's invoked for a type that has more
than one instance -- client code should never do that. visitWidgets
now visits all widgets of the specified type.