How to use the flattentool.exceptions.DataErrorWarning function in flattentool

def dict_to_xml(data, tagname, toplevel=True, nsmap=None):
    if USING_LXML and ":" in tagname and not toplevel:
        tagname = (
            "{"
            + nsmap.get(tagname.split(":", 1)[0], "")
            + "}"
            + tagname.split(":", 1)[1]
        )
    try:
        if USING_LXML:
            el = ET.Element(tagname, nsmap=nsmap)
        else:
            el = ET.Element(tagname)
    except ValueError as e:
        warn(str(e), DataErrorWarning)
        return

    if USING_LXML:
        data = sort_attributes(data)

    for k, v in data.items():
        if type(v) == list:
            for item in v:
                child_to_xml(el, k, item, nsmap=nsmap)
        else:
            child_to_xml(el, k, v, toplevel=toplevel, nsmap=nsmap)
    return el

elif type_string in ("array", "array_array", "string_array", "number_array"):
        value = str(value)
        if type_string == "number_array":
            try:
                if "," in value:
                    return [
                        [Decimal(y) for y in x.split(",")] for x in value.split(";")
                    ]
                else:
                    return [Decimal(x) for x in value.split(";")]
            except (TypeError, ValueError, InvalidOperation):
                warn(
                    'Non-numeric value "{}" found in number array column, returning as string array instead.'.format(
                        value
                    ),
                    DataErrorWarning,
                )
        if "," in value:
            return [x.split(",") for x in value.split(";")]
        else:
            return value.split(";")
    elif type_string == "string":
        if type(value) == datetime.datetime:
            return timezone.localize(value).isoformat()
        return str(value)
    elif type_string == "date":
        if type(value) == datetime.datetime:
            return value.date().isoformat()
        return str(value)
    elif type_string == "":
        if type(value) == datetime.datetime:
            return timezone.localize(value).isoformat()

)
                    )
                list_index = int(next_path_item)
                current_type = "array"

            if current_type == "array":
                list_as_dict = current_path.get(path_item)
                if list_as_dict is None:
                    list_as_dict = ListAsDict()
                    current_path[path_item] = list_as_dict
                elif type(list_as_dict) is not ListAsDict:
                    warn(
                        "Column {} has been ignored, because it treats {} as an array, but another column does not.".format(
                            path, path_till_now
                        ),
                        DataErrorWarning,
                    )
                    break
                new_path = list_as_dict.get(list_index)
                if new_path is None:
                    new_path = OrderedDict()
                    list_as_dict[list_index] = new_path
                current_path = new_path
                if not xml or num < len(path_list) - 2:
                    # In xml "arrays" can have text values, if they're the final element
                    # This corresponds to a tag with text, but also possibly attributes
                    continue

            ## Object
            if current_type == "object" or (not current_type and next_path_item):
                new_path = current_path.get(path_item)
                if new_path is None:

sheet_header = list(sheet)
        worksheet = self.workbook.create_sheet()
        worksheet.title = self.sheet_prefix + sheet_name
        worksheet.append(sheet_header)
        for sheet_line in sheet.lines:
            line = []
            for header in sheet_header:
                value = sheet_line.get(header)
                if isinstance(value, str):
                    new_value = ILLEGAL_CHARACTERS_RE.sub("", value)
                    if new_value != value:
                        warn(
                            "Character(s) in '{}' are not allowed in a spreadsheet cell. Those character(s) will be removed".format(
                                value
                            ),
                            DataErrorWarning,
                        )
                    value = new_value
                line.append(value)
            worksheet.append(line)