def METHOD_NAME(self, default_config):
    """Test setting items."""
    # set existing options
    default_config["main.shots"] = 10
    assert default_config["main.shots"] == 10
    assert default_config["main"]["shots"] == 10
    default_config["strawberryfields.global"]["hbar"] = 5
    assert default_config["strawberryfields.global.hbar"] == 5
    assert default_config["strawberryfields.global"]["hbar"] == 5
    # set new options
    default_config["qiskit.ibmq"]["backend"] = "ibmq_rome"
    assert default_config["qiskit.ibmq.backend"] == "ibmq_rome"
    # set nested dictionaries
    default_config["strawberryfields.tf"] = {"batched": True, "cutoff_dim": 6}
    assert default_config["strawberryfields.tf"] == {"batched": True, "cutoff_dim": 6}
    # set nested keys that don't exist dictionaries
    default_config["strawberryfields.another.hello.world"] = 5
    assert default_config["strawberryfields.another"] == {"hello": {"world": 5}}