'A tuple containing the ``Tkinter.Label`` widgets used to
display the label of each column.  If this multi-column
listbox was created without labels, then this will be an empty
tuple.  These widgets will all be augmented with a
``column_index`` attribute, which can be used to determine
which column they correspond to.  This can be convenient,
e.g., when defining callbacks for bound events.'

@property
def column_labels(self):

    return tuple(self._labels)
