'Function to return the size a flowable will require'

def get_flowable_size(self, flowable):

    if (not flowable):
        return (0, 0)
    if (not isinstance(flowable, list)):
        flowable = [flowable]
    w = 0
    h = 0
    for f in flowable:
        if f:
            size = f.wrap(self.printable_width, self.printable_height)
            if (size[0] > w):
                w = size[PDF_WIDTH]
            h += size[PDF_HEIGHT]
    return (w, h)
