Updates row_heights in code_array

def _xls2row_heights(self, worksheet, tab):
        """Updates row_heights in code_array"""

        for row in xrange(worksheet.nrows):
            try:
                height_points = worksheet.rowinfo_map[row].height / 20.0
                height_inches = height_points / 72.0
                height_pixels = height_inches * get_dpi()[1]

                self.code_array.row_heights[row, tab] = height_pixels

            except KeyError:
                pass