I am working on Odoo 10 and I am working on creating xlsx file and i am almost done because i created file successfully but the next i want to do is to add the currently created file into database table `ir.attachment` and my column requires bytea data so i need to convert the file in binary data. Which i tried in last line but its giving me error AttributeError: 'Workbook' object has no attribute 'read'. Below is the code from my function which i am using/

   file_name = 'test'
    workbook = xlsxwriter.Workbook(file_name)
    bold = workbook.add_format({'bold': True})  # Add a bold format to use to highlight cells.
    row_count = 2
    for customer in customers:
        customer_orders = self.env['amgl.order_line'].search([('customer_id', '=', customer.id)])
        column_count = 0
        for customer_order in customer_orders:
            worksheet.write(row_count, column_count, 'GST_Customer_account_number')
            column_count += 1
            worksheet.write(row_count, column_count, customer.full_name)
            column_count += 1
            worksheet.write(row_count, column_count, customer.account_number)
            column_count += 1
            worksheet.write(row_count, column_count, customer_order.create_date)
            column_count += 1
            worksheet.write(row_count, column_count, 'PR')
            column_count += 1
            worksheet.write(row_count, column_count, customer_order.products.product_code)
            column_count += 1
            worksheet.write(row_count, column_count, customer_order.quantity)
            column_count += 1
            worksheet.write(row_count, column_count, 'amark')
            column_count += 1
            worksheet.write(row_count, column_count, 'amark_customer_code')
            column_count += 1
            worksheet.write(row_count, column_count, 'Descripion')
            column_count += 1
            worksheet.write(row_count, column_count, 'transaction_number')
            row_count += 1

    workbook.close()
    data = 0
    base64.encode(workbook, data)

Update

 I tried to do followings and its making my encoded.But now i face issue that whenever i sent that record as an attachment. The file shows me the binary not actual text.

Here is what i tried.

with open(file_name, "rb") as xlfile:
    byte_data = xlfile.read()

test_id = self.env['ir.attachment'].create({'name': file_name,
    'datas': byte_data,
    'datas_fname': file_name,
    'res_model': 'res.users',
    'res_id': 1, })
template = self.env.ref('amgl.mmr_approval_complete', raise_if_not_found=True)
mail_id = template.with_context(mmr_name='Export Report').send_mail(
    1,
    force_send=True,
    raise_exception=True,
    email_values={'attachment_ids': [test_id.id]}
)

I added these lines after workbook.close()