Returns a container for the inputed entry widget.
        
        :param      entry | <XOrbQueryEntryWidget>
        
        :return     <XOrbQueryContainer> || None

def containerFor(self, entry):
        """
        Returns a container for the inputed entry widget.
        
        :param      entry | <XOrbQueryEntryWidget>
        
        :return     <XOrbQueryContainer> || None
        """
        try:
            index = self._compoundStack.index(entry)
        except ValueError:
            return None
        
        return self.widget(index + 1)