How to use the unicodecsv.excel function in unicodecsv

# TODO: check if it impacts in memory usage.
# TODO: may add option to change it by passing a parameter to import/export.
unicodecsv.field_size_limit(16777216)


def fix_dialect(dialect):
    if not dialect.doublequote and dialect.escapechar is None:
        dialect.doublequote = True

    if dialect.quoting == unicodecsv.QUOTE_MINIMAL and dialect.quotechar == "'":
        # Python csv's Sniffer seems to detect a wrong quotechar when
        # quoting is minimal
        dialect.quotechar = '"'


class excel_semicolon(unicodecsv.excel):
    delimiter = ';'

unicodecsv.register_dialect("excel-semicolon", excel_semicolon)


if six.PY2:

    def discover_dialect(sample, encoding=None, delimiters=(b",", b";", b"\t", b"|")):
        """Discover a CSV dialect based on a sample size.

        `encoding` is not used (Python 2)
        """
        try:
            dialect = sniffer.sniff(sample, delimiters=delimiters)

        except unicodecsv.Error:  # Couldn't detect: fall back to 'excel'

    def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
        # Redirect output to a queue
        self.stream = f
        self.writer = writer = csv.writer(f, dialect=dialect, **kwds)
        self.lock = threading.RLock()

import unicodecsv as csv


class DocdataDialect(csv.excel):
    """ Docdata CSV dialect. """
    delimiter = '\t'

def discover_dialect(sample, encoding=None, delimiters=(b",", b";", b"\t", b"|")):
        """Discover a CSV dialect based on a sample size.

        `encoding` is not used (Python 2)
        """
        try:
            dialect = sniffer.sniff(sample, delimiters=delimiters)

        except unicodecsv.Error:  # Couldn't detect: fall back to 'excel'
            dialect = unicodecsv.excel

        fix_dialect(dialect)
        return dialect

def render_to_csv(self, context):
        statement = context['statement']
        response = HttpResponse(content_type='text/csv')
        response['Content-Disposition'] = 'attachment; filename="financialStatementByEvent.csv"'

        writer = csv.writer(response, csv.excel)
        response.write(u'\ufeff'.encode('utf8'))  # BOM (optional...Excel needs it to open UTF-8 file properly)

        header_list = [
            _('Event'),
            _('Month'),
            _('Registrations: Total'),
            _('Registrations: Leads'),
            _('Registrations: Follows'),
            _('Revenues: Gross'),
            _('Revenues: Net'),
            _('Expenses: Instruction'),
            _('Expenses: Venue'),
            _('Expenses: Other'),
            _('Expenses: Total'),
            _('Net Profit'),
        ]

def getRevenueItemsCSV(queryset):
    response = HttpResponse(content_type='text/csv')
    response['Content-Disposition'] = 'attachment; filename="revenueHistory.csv"'

    writer = csv.writer(response, csv.excel)
    response.write(u'\ufeff'.encode('utf8'))  # BOM (optional...Excel needs it to open UTF-8 file properly)

    header_list = [
        _('Description'),
        _('Revenue Category'),
        _('Gross Total (Pre-Discounts & Vouchers)'),
        _('Net Total'),
        _('Received From'),
        _('Registration'),
        _('Event'),
        _('Received'),
        _('Received Date')
    ]
    writer.writerow(header_list)

    for x in queryset:

def getExpenseItemsCSV(queryset, scope='instructor'):

    response = HttpResponse(content_type='text/csv')
    if scope == 'instructor':
        response['Content-Disposition'] = 'attachment; filename="paymentHistory.csv"'
    else:
        response['Content-Disposition'] = 'attachment; filename="expenseHistory.csv"'

    writer = csv.writer(response, csv.excel)
    response.write(u'\ufeff'.encode('utf8'))  # BOM (optional...Excel needs it to open UTF-8 file properly)

    header_list = [
        _('Description'),
        _('Expense Category'),
        _('Hours'),
        _('Wage Rate'),
        _('Total Payment'),
        _('Is Reimbursement'),
        _('Submission Date'),
        _('Event'),
        _('Approved'),
        _('Paid'),
        _('Payment Date'),
    ]

decoded = sample.decode(encoding)

            except UnicodeDecodeError as exception:
                _, _, _, pos, error = exception.args
                if error == "unexpected end of data" and pos == len(sample):
                    sample = sample[:-1]
                else:
                    raise
            else:
                finished = True

        try:
            dialect = sniffer.sniff(decoded, delimiters=delimiters)

        except unicodecsv.Error:  # Couldn't detect: fall back to 'excel'
            dialect = unicodecsv.excel

        fix_dialect(dialect)
        return dialect

def unicode_csv_reader(csv_data, dialect=csv.excel, charset='utf-8', **kwargs):
    csv_reader = csv.reader(csv_data, dialect=dialect, encoding=charset, **kwargs)
    for row in csv_reader:
        yield row

def export_to_csv(
    table,
    filename_or_fobj=None,
    encoding="utf-8",
    dialect=unicodecsv.excel,
    batch_size=100,
    callback=None,
    *args,
    **kwargs
):
    """Export a `rows.Table` to a CSV file.


    If a file-like object is provided it MUST be in binary mode, like in
    `open(filename, mode='wb')`.
    If not filename/fobj is provided, the function returns a string with CSV
    contents.
    """
    # TODO: will work only if table.fields is OrderedDict
    # TODO: should use fobj? What about creating a method like json.dumps?