def empty(self, process_tile):
bands = (<EOL>self.output_params["<STR_LIT>"]<EOL>if "<STR_LIT>" in self.output_params<EOL>else PNG_DEFAULT_PROFILE["<STR_LIT:count>"]<EOL>)<EOL>return ma.masked_array(<EOL>data=ma.zeros((bands, ) + process_tile.shape),<EOL>mask=ma.zeros((bands, ) + process_tile.shape),<EOL>dtype=PNG_DEFAULT_PROFILE["<STR_LIT>"]<EOL>)<EOL>
Return empty data.

Parameters
----------
process_tile : ``BufferedTile``
    must be member of process ``TilePyramid``

Returns
-------
empty data : array
    empty array with data type given in output parameters