How to use the bugwarrior.services.get_service function in bugwarrior

def build_key_list(targets):
    from bugwarrior.services import get_service

    keys = {}
    for target in targets:
        keys[target] = get_service(target).ISSUE_CLASS.UNIQUE_KEY
    return keys

targets = [t for t in targets if len(t)]

    if not targets:
        die("Empty targets= item in [%s]." % main_section)

    for target in targets:
        if target not in config.sections():
            die("No [%s] section found." % target)

    # Validate each target one by one.
    for target in targets:
        service = config.get(target, 'service')
        if not service:
            die("No 'service' in [%s]" % target)

        if not get_service(service):
            die("'%s' in [%s] is not a valid service." % (service, target))

        # Call the service-specific validator
        service = get_service(service)
        service_config = ServiceConfig(service.CONFIG_PREFIX, config, target)
        service.validate_config(service_config, target)

for target in targets:
        if target not in config.sections():
            die("No [%s] section found." % target)

    # Validate each target one by one.
    for target in targets:
        service = config.get(target, 'service')
        if not service:
            die("No 'service' in [%s]" % target)

        if not get_service(service):
            die("'%s' in [%s] is not a valid service." % (service, target))

        # Call the service-specific validator
        service = get_service(service)
        service_config = ServiceConfig(service.CONFIG_PREFIX, config, target)
        service.validate_config(service_config, target)

'type': 'string',
                },
                'serviceBnumber': {
                    'label': 'Service B Number',
                    'type': 'numeric',
                }
            }
        }

    """

    from bugwarrior.services import get_service

    targets_udas = {}
    for target in targets:
        targets_udas.update(get_service(target).ISSUE_CLASS.UDAS)
    return {
        'uda': targets_udas
    }

def targets():
    config = load_config('general')
    for section in config.sections():
        if section in ['general', 'notifications'] or \
           section.startswith('flavor.'):
            continue
        service_name = config.get(section, 'service')
        service_class = get_service(service_name)
        for option in config.options(section):
            value = config.get(section, option)
            if not value:
                continue
            if '@oracle:use_keyring' in value:
                service_config = ServiceConfig(
                    service_class.CONFIG_PREFIX, config, section)
                yield service_class.get_keyring_service(service_config)