<filename>src/restaurants/validators.py
from django.core.exceptions import ValidationError

CATEGORIES = ['Persian', 'American', 'Asian']

def validate_category(value):
    cat = value.capitalize()
    if not value in CATEGORIES and not cat in CATEGORIES:
        raise ValidationError(f'{value} is not an valid category')

<filename>src/restaurants/validators.py
from django.core.exceptions import ValidationError

CATEGORIES = ['Persian', 'American', 'Asian']

def validate_category(value):
    cat = value.capitalize()
    if not value in CATEGORIES and not cat in CATEGORIES:
        raise ValidationError(f'{value} is not an valid category')
