'Parameters
pad : float, optional
Boundary pad.
sep : float, optional
Spacing between items.
width : float, optional
height : float, optional
Width and height of the container box, calculated if
`None`.
align : str, optional
Alignment of boxes. Can be one of ``top``, ``bottom``,
``left``, ``right``, ``center`` and ``baseline``
mode : str, optional
Packing mode.
Notes
*pad* and *sep* need to given in points and will be scale with
the renderer dpi, while *width* and *height* need to be in
pixels.'

def __init__(self, pad=None, sep=None, width=None, height=None, align=None, mode=None, children=None):

    super(PackerBase, self).__init__()
    self.height = height
    self.width = width
    self.sep = sep
    self.pad = pad
    self.mode = mode
    self.align = align
    self._children = children
