How to use the betelgeuse.load_custom_fields function in Betelgeuse

def test_load_custom_fields_none():
    """Check if None value return empty dict for custom fields."""
    assert load_custom_fields(None) == {}

def test_load_custom_fields_empty():
    """Check if empty value return empty dict for custom fields."""
    assert load_custom_fields(('',)) == {}

def test_load_custom_fields():
    """Check if custom fields can be loaded using = notation."""
    assert load_custom_fields(('isautomated=true',)) == {
        'isautomated': 'true'
    }

def test_load_custom_fields_json():
    """Check if custom fields can be loaded using JSON data."""
    assert load_custom_fields(('{"isautomated":true}',)) == {
        'isautomated': True,
    }