Updates col_widths in code_array

def _xls2col_widths(self, worksheet, tab):
        """Updates col_widths in code_array"""

        for col in xrange(worksheet.ncols):
            try:
                xls_width = worksheet.colinfo_map[col].width
                pys_width = self.xls_width2pys_width(xls_width)
                self.code_array.col_widths[col, tab] = pys_width

            except KeyError:
                pass