How to use the routingpy.routers.base.DEFAULT function in routingpy

def __init__(
            self,
            api_key,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs=None,
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes a Valhalla client.

        :param api_key: Mapbox API key.
        :type api_key: str

        :param user_agent: User Agent to be used when requesting.
            Default :attr:`routingpy.routers.options.default_user_agent`.
        :type user_agent: str

        :param timeout: Combined connect and read timeout for HTTP requests, in

def __init__(
            self,
            base_url,
            api_key=None,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs=None,
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes a Valhalla client.

        :param api_key: Mapbox API key. Required if base_url='https://api.mapbox.com/valhalla/v1'.
        :type api_key: str

        :param base_url: The base URL for the request. Defaults to the ORS API
            server. Should not have a trailing slash.
        :type base_url: str

        :param user_agent: User Agent to be used when requesting.

def __init__(
            self,
            base_url=_DEFAULT_BASE_URL,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs=None,
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes an OSRM client.

        :param base_url: The base URL for the request. Defaults to the OSRM demo API
            server. Should not have a trailing slash.
        :type base_url: str

        :param user_agent: User Agent to be used when requesting.
            Default :attr:`routingpy.routers.options.default_user_agent`.
        :type user_agent: str

def __init__(
            self,
            api_key,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs=None,
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes a Mapbox OSRM client.

        :param api_key: Mapbox API key.
        :type api_key: str

        :param user_agent: User Agent to be used when requesting.
            Default :attr:`routingpy.routers.options.default_user_agent`.
        :type user_agent: str

        :param timeout: Combined connect and read timeout for HTTP requests, in

def __init__(
        self,
        app_id=None,
        app_code=None,
        user_agent=None,
        timeout=DEFAULT,
        retry_timeout=None,
        requests_kwargs=None,
        retry_over_query_limit=False,
        skip_api_error=None
    ):
        """
        Initializes a HERE Maps client.

        :param app_id: HERE Maps app id. 
        :type app_id: str

        :param app_code: HERE Maps app code.
        :type app_code: str

        :param user_agent: User Agent to be used when requesting.
            Default :attr:`routingpy.routers.options.default_user_agent`.

def __init__(
            self,
            api_key=None,
            base_url=_DEFAULT_BASE_URL,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs={},
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes an graphhopper client.

        :param api_key: GH API key. Required if https://graphhopper.com/api is used.
        :type api_key: str

        :param base_url: The base URL for the request. Defaults to the ORS API
            server. Should not have a trailing slash.
        :type base_url: str

        :param user_agent: User Agent to be used when requesting.

def __init__(
            self,
            api_key,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs={},
            retry_over_query_limit=True,
            skip_api_error=None
    ):
        """
        Initializes a Google client.

        :param key: API key.
        :type key: str

        :param user_agent: User Agent to be used when requesting.
            Default :attr:`routingpy.routers.options.default_user_agent`.
        :type user_agent: str

        :param timeout: Combined connect and read timeout for HTTP requests, in

def __init__(
            self,
            api_key=None,
            base_url=_DEFAULT_BASE_URL,
            user_agent=None,
            timeout=DEFAULT,
            retry_timeout=None,
            requests_kwargs=None,
            retry_over_query_limit=False,
            skip_api_error=None
    ):
        """
        Initializes an openrouteservice client.

        :param api_key: ORS API key. Required if https://api.openrouteservice.org is used.
        :type api_key: str

        :param base_url: The base URL for the request. Defaults to the ORS API
            server. Should not have a trailing slash.
        :type base_url: str

        :param user_agent: User Agent to be used when requesting.