How to use the avalara.client.AvataxClient function in Avalara

def test_client_can_be_created(unauth_client):
    """Test that the client object can be created."""
    assert isinstance(unauth_client, AvataxClient)

def test_client_can_obtain_their_own_base_url():
    """Test the client can input a url as the base url."""
    client = AvataxClient('test app', 'ver 0.0', 'test machine', 'https://myurl.com')
    assert client.base_url == 'https://myurl.com'

def test_client_can_obtain_production_url_as_base_url():
    """Test the default option for base url is production url."""
    client = AvataxClient('test app', 'ver 0.0', 'test machine')
    assert client.base_url == 'https://rest.avatax.com'

def test_auth_able_to_call_and_return_self(unauth_client):
    """Test client can call add_cred method and returns an avatax client obj."""
    assert isinstance(unauth_client.add_credentials(), AvataxClient)