Add extra datas to the last row
        headers : [col1, col2, col3, col4, col5]
        row : {col1: a1, col2: a2, col3: a3}
        extra_datas : [a4, a5]

        row becomes : {col1: a1, col2: a2, col3: a3, col4: a4, col5: a5}

        in case of longer extra_datas, the last columns will be overriden

        :param list extra_datas: list of values to set in the last columns

def add_extra_datas(self, extra_datas):
        """
        Add extra datas to the last row
        headers : [col1, col2, col3, col4, col5]
        row : {col1: a1, col2: a2, col3: a3}
        extra_datas : [a4, a5]

        row becomes : {col1: a1, col2: a2, col3: a3, col4: a4, col5: a5}

        in case of longer extra_datas, the last columns will be overriden

        :param list extra_datas: list of values to set in the last columns
        """
        # we will add datas starting from the last index
        for index, data in enumerate(extra_datas):
            header = self.extra_headers[index]
            self._datas[-1][header['label']] = data