Writes row_heights to pys file

        Format: <row>\t<tab>\t<value>\n

def _row_heights2pys(self):
        """Writes row_heights to pys file

        Format: <row>\t<tab>\t<value>\n

        """

        for row, tab in self.code_array.dict_grid.row_heights:
            if row < self.code_array.shape[0] and \
               tab < self.code_array.shape[2]:
                height = self.code_array.dict_grid.row_heights[(row, tab)]
                height_strings = map(repr, [row, tab, height])
                self.pys_file.write(u"\t".join(height_strings) + u"\n")