"""DB field validators"""
import xml.etree.cElementTree as et

from django.core.exceptions import ValidationError


def svg_image_validator(file: object) -> object:
    """Validate SVG file"""
    tag = None
    try:
        for event, el in et.iterparse(file, ('start',)):
            tag = el.tag
            break
        assert tag == '{http://www.w3.org/2000/svg}svg'
    except:
        raise ValidationError(
            message='Invalid SVG image file',
            code='invalid_svg_image',
            params={'value': file},
        )
    else:
        return file