Issue importing with char "="

With csv is not necessary process the fields as calculated formula, is getting a error when have the char "=".

• https://lab.civicrm.org/extensions/advimport/blob/master/CRM/Advimport/Helper/PHPExcel.php#L102

toArray($nullValue = null, $calculateFormulas = true, $formatData = true, $returnCellRef = false)