pip install cerberus python from cerberus import Validator python def validate_phone(field, value, error): if not re.match(r'^\+?1?\d{9,15}$', value): error(field, "Invalid phone number") python v = Validator() v.validators['phone'] = validate_phone python document = {'phone': '1234567890'} if v.validate(document): print("Validation successful") else: print(v.errors) python import re from cerberus import Validator def validate_phone(field, value, error): if not re.match(r'^\+?1?\d{9,15}$', value): error(field, "Invalid phone number") v = Validator() v.validators['phone'] = validate_phone document = {'phone': '1234567890'} if v.validate(document): print("Validation successful") else: print(v.errors)