Getting Error Message

[ranagoutam]

Illegal assignment of '904567891484' to 'value' in class Ean13BarcodeWidget

my model is as

class Items(models.Model):
i_date = models.DateTimeField(auto_now_add=True,verbose_name="item Date")
barcode = models.CharField(primary_key=True, max_length=24, verbose_name="item Id", help_text="place the barcode here")

view.py:

def barId_report(request):
resp = HttpResponse(mimetype='application/pdf')
item_list = Items.objects.all()
report = SimpleListReport(queryset=item_list)
report.generate_by(PDFGenerator, filename=resp)

    return resp

report.py

the normal one as given on the examples with code replaced to barcode.

By my gesture it is some problem arising due to the data retieved from my model as Unicode.
How to Over Come please help..