def to_python(self, data):
        if data in validators.EMPTY_VALUES:
            return None

        # UploadedFile objects should have name and size attributes.
        try:
            file_name = data.name
            file_size = data.size
        except __HOLE__:
            raise ValidationError(self.error_messages['invalid'])

        if self.max_length is not None and len(file_name) > self.max_length:
            error_values =  {'max': self.max_length, 'length': len(file_name)}
            raise ValidationError(self.error_messages['max_length'] % error_values)
        if not file_name:
            raise ValidationError(self.error_messages['invalid'])
        if not file_size:
            raise ValidationError(self.error_messages['empty'])

        return data
dataset/ETHPy150Open adieu/django-nonrel/django/forms/fields.py/FileField.to_python