def read(self, output_tile, **kwargs):
try:<EOL><INDENT>return ma.masked_values(<EOL>read_raster_no_crs(<EOL>self.get_path(output_tile), indexes=(<NUM_LIT:4> if self.old_band_num else <NUM_LIT:2>)<EOL>),<EOL><NUM_LIT:0><EOL>)<EOL><DEDENT>except FileNotFoundError:<EOL><INDENT>return self.empty(output_tile)<EOL><DEDENT>
Read existing process output.

Parameters
----------
output_tile : ``BufferedTile``
    must be member of output ``TilePyramid``

Returns
-------
process output : ``BufferedTile`` with appended data