def METHOD_NAME(self):
    feature_flag_data = schemas.FeatureFlagSchema(
        flagKey="flag_2",
        variants=[
            schemas.FeatureFlagVariant(
                value="Variant 1",
                description="Description 1",
                # payload="{'key': 'value1'}",
                rolloutPercentage=50
            ),
            schemas.FeatureFlagVariant(
                value="Variant 2",
                description="Description 2",
                # payload="{'key': 'value1'}",
                rolloutPercentage=50
            )
        ]
    )
    expected_output = {
        "v_value_0": "Variant 1",
        "v_description_0": "Description 1",
        # "payload_0": json.dumps({"key": "value1"}),
        'v_payload_0': 'null',
        "v_rollout_percentage_0": 50,
        "v_value_1": "Variant 2",
        "v_description_1": "Description 2",
        # "payload_1": json.dumps({"key": "value2"}),
        'v_payload_1': 'null',
        "v_rollout_percentage_1": 50
    }
    assert prepare_variants_values(feature_flag_data) == expected_output