def splity(self, *args):
boxes = []<EOL>yf = [<NUM_LIT:0>] + list(args) + [<NUM_LIT:1>]<EOL>x0, y0, x1, y1 = self._get_extents()<EOL>h = y1 - y0<EOL>for yf0, yf1 in zip(yf[:-<NUM_LIT:1>], yf[<NUM_LIT:1>:]):<EOL><INDENT>boxes.append(Bbox([[x0, y0 + yf0 * h], [x1, y0 + yf1 * h]]))<EOL><DEDENT>return boxes<EOL>
e.g., ``bbox.splitx(f1, f2, ...)``

Returns a list of new :class:`Bbox` objects formed by
splitting the original one with horizontal lines at fractional
positions *f1*, *f2*, ...