How to use the pyisemail.diagnosis.BaseDiagnosis.CATEGORIES function in pyIsEmail

from testscenarios import TestWithScenarios
from unittest import TestCase
try:
    from unittest.mock import patch
except ImportError:
    from mock import patch
import dns.resolver
from pyisemail import is_email
from pyisemail.diagnosis import BaseDiagnosis, DNSDiagnosis
from tests.validators import create_diagnosis, get_scenarios


class IsEmailTest(TestWithScenarios):

    scenarios = get_scenarios("tests.xml")
    threshold = BaseDiagnosis.CATEGORIES['THRESHOLD']

    def test_without_diagnosis(self):
        result = is_email(self.address)
        expected = create_diagnosis(self.diagnosis) < self.threshold

        self.assertEqual(
            result,
            expected,
            ("%s (%s): Got %s, but expected %s."
             % (self.id, self.address, result, expected))
        )

    def test_with_diagnosis(self):
        result = is_email(self.address, diagnose=True)
        expected = create_diagnosis(self.diagnosis)

def is_email(address, check_dns=False, diagnose=False):
    """Validate an email address.

    Keyword arguments:
    address   --- the email address as a string
    check_dns --- flag for whether to check the DNS status of the domain
    diagnose  --- flag for whether to return True/False or a Diagnosis

    """

    threshold = BaseDiagnosis.CATEGORIES["THRESHOLD"]
    d = ParserValidator().is_email(address, True)
    if check_dns is True and d < BaseDiagnosis.CATEGORIES["DNSWARN"]:
        threshold = BaseDiagnosis.CATEGORIES["VALID"]
        d = max(d, DNSValidator().is_valid(address.split("@")[1], True))

    return d if diagnose else d < threshold

"""Check that an address address conforms to RFCs 5321, 5322 and others.

        More specifically, see the follow RFCs:
            * http://tools.ietf.org/html/rfc5321
            * http://tools.ietf.org/html/rfc5322
            * http://tools.ietf.org/html/rfc4291#section-2.2
            * http://tools.ietf.org/html/rfc1123#section-2.1
            * http://tools.ietf.org/html/rfc3696) (guidance only)

        Keyword arguments:
        address    -- address to check.
        diagnose   -- flag to report a diagnosis or a boolean (default False)

        """

        threshold = BaseDiagnosis.CATEGORIES['VALID']
        return_status = [ValidDiagnosis()]
        parse_data = {}

        # Parse the address into components, character by character
        raw_length = len(address)
        context = Context.LOCALPART              # Where we are
        context_stack = [context]                # Where we've been
        context_prior = Context.LOCALPART        # Where we just came from
        token = ''                               # The current character
        token_prior = ''                         # The previous character
        parse_data[Context.LOCALPART] = ''       # The address' components
        parse_data[Context.DOMAIN] = ''
        atom_list = {
            Context.LOCALPART: [''],
            Context.DOMAIN: ['']
        }                                        # The address' dot-atoms

def validate_email(email_string):
    d = is_email(email_string, diagnose=True)
    if d > BaseDiagnosis.CATEGORIES["VALID"]:
        raise SwaggerValidationError(f"{email_string} {d.message}")