|spacing = 10||Horizontal space to leave between items.|
|padding = (0, 0)||Space to leave horizontally and vertically around all the items.|
|align = 'c'||Specifies vertical alignment and anchoring of items. One of 't', 'c', 'b' or 'tb' for top, centre, bottom or top-and-bottom.|
|equalize = ''||Specifies whether to make the size of all items equal in the horizontal and/or vertical direction. One of 'w', 'h' or 'wh'.|
|expand = None||Specifies
which item, if any, is to change size horizontally when the container
is resized. May be the item itself or an index into the item list.
Items to the left of this item will be anchored to the left of
the container, and items to the right will be anchored to the
right of the container.|
If specified by an index, the item at that index may be None to leave an expanding space in the row.