def METHOD_NAME(self):
    config = Configuration.instantiate()
    result = braintree.Customer.create()
    customer_id = result.customer.id
    client_token = TestHelper.generate_decoded_client_token({
        "customer_id": customer_id,
        "options": {
            "make_default": True
        }
    })
    authorization_fingerprint = json.loads(client_token)["authorizationFingerprint"]
    http = ClientApiHttp(config, {
        "authorization_fingerprint": authorization_fingerprint,
        "shared_customer_identifier": "fake_identifier",
        "shared_customer_identifier_type": "testing"
    })
    status_code, _ = http.add_card({
        "credit_card": {
            "number": "4111111111111111",
            "expiration_month": "11",
            "expiration_year": "2099",
        }
    })
    self.assertEqual(201, status_code)
    status_code, _ = http.add_card({
        "credit_card": {
            "number": "4005519200000004",
            "expiration_month": "11",
            "expiration_year": "2099",
        }
    })
    self.assertEqual(201, status_code)
    customer = braintree.Customer.find(customer_id)
    self.assertEqual(2, len(customer.credit_cards))
    for credit_card in customer.credit_cards:
        if credit_card.bin == "400551":
            self.assertTrue(credit_card.default)