def load_config_file(self, suppress_errors=IPYTHON_SUPPRESS_CONFIG_ERRORS):
        """Load the config file.

        By default, errors in loading config are handled, and a warning
        printed on screen. For testing, the suppress_errors option is set
        to False, so errors will make tests fail.

        `supress_errors` default value is to be `None` in which case the
        behavior default to the one of `traitlets.Application`.

        The default value can be set :
           - to `False` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '0', or 'false' (case insensitive).
           - to `True` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '1' or 'true' (case insensitive).
           - to `None` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '' (empty string) or leaving it unset.

        Any other value are invalid, and will make IPython exit with a non-zero return code.
        """

        self.log.debug("Searching path %s for config files", self.config_file_paths)
        base_config = "ipython_config.py"
        self.log.debug("Attempting to load config file: %s" % base_config)
        try:
            if suppress_errors is not None:
                old_value = Application.raise_config_file_errors
                Application.raise_config_file_errors = not suppress_errors
            Application.load_config_file(self, base_config, path=self.config_file_paths)
        except ConfigFileNotFound:
            # ignore errors loading parent
            self.log.debug("Config file %s not found", base_config)
            pass
        if suppress_errors is not None:
            Application.raise_config_file_errors = old_value

        for config_file_name in self.config_files:
            if not config_file_name or config_file_name == base_config:
                continue
            self.log.debug("Attempting to load config file: %s" % self.config_file_name)
            try:
                Application.load_config_file(self, config_file_name, path=self.config_file_paths)
            except ConfigFileNotFound:
                # Only warn if the default config file was NOT being used.
                if config_file_name in self.config_file_specified:
                    msg = self.log.warning
                else:
                    msg = self.log.debug
                msg("Config file not found, skipping: %s", config_file_name)
            except Exception:
                # For testing purposes.
                if not suppress_errors:
                    raise
                self.log.warning("Error loading config file: %s" % self.config_file_name, exc_info=True)

    def pylab(self, line=""):
        """Load numpy and matplotlib to work interactively.

        This function lets you activate pylab (matplotlib, numpy and
        interactive support) at any point during an IPython session.
        
        %pylab makes the following imports::
        
            import numpy
            import matplotlib
            from matplotlib import pylab, mlab, pyplot
            np = numpy
            plt = pyplot
            
            from IPython.display import display
            from IPython.core.pylabtools import figsize, getfigs
            
            from pylab import *
            from numpy import *

        If you pass `--no-import-all`, the last two `*` imports will be excluded.
        
        See the %matplotlib magic for more details about activating matplotlib
        without affecting the interactive namespace.
        """
        args = magic_arguments.parse_argstring(self.pylab, line)
        if args.no_import_all is None:
            # get default from Application
            if Application.initialized():
                app = Application.instance()
                try:
                    import_all = app.pylab_import_all
                except AttributeError:
                    import_all = True
            else:
                # nothing specified, no classes - default True
                import_all = True
        else:
            # invert no-import flag
            import_all = not args.no_import_all

        gui, backend, clobbered = self.shell.enable_pylab(args.gui, import_all=import_all)
        self._show_matplotlib_backend(args.gui, backend)
        print("Populating the interactive namespace from numpy and matplotlib")
        if clobbered:
            warn(
                "pylab import has clobbered these variables: %s" % clobbered
                + "\n`%matplotlib` prevents importing * from pylab and numpy"
            )

def enable_gui(gui, kernel=None):
    """Enable integration with a given GUI"""
    if gui not in loop_map:
        e = "Invalid GUI request %r, valid ones are:%s" % (gui, loop_map.keys())
        raise ValueError(e)
    if kernel is None:
        if Application.initialized():
            kernel = getattr(Application.instance(), 'kernel', None)
        if kernel is None:
            raise RuntimeError("You didn't specify a kernel,"
                " and no IPython Application with a kernel appears to be running."
            )
    loop = loop_map[gui]
    if loop and kernel.eventloop is not None and kernel.eventloop is not loop:
        raise RuntimeError("Cannot activate multiple GUI eventloops")
    kernel.eventloop = loop

    def load_config_file(self, suppress_errors=True):
        """Load the config file.

        By default, errors in loading config are handled, and a warning
        printed on screen. For testing, the suppress_errors option is set
        to False, so errors will make tests fail.
        """
        self.log.debug("Searching path %s for config files", self.config_file_paths)
        base_config = 'ipython_config.py'
        self.log.debug("Attempting to load config file: %s" %
                       base_config)
        try:
            Application.load_config_file(
                self,
                base_config,
                path=self.config_file_paths
            )
        except ConfigFileNotFound:
            # ignore errors loading parent
            self.log.debug("Config file %s not found", base_config)
            pass
        
        for config_file_name in self.config_files:
            if not config_file_name or config_file_name == base_config:
                continue
            self.log.debug("Attempting to load config file: %s" %
                           self.config_file_name)
            try:
                Application.load_config_file(
                    self,
                    config_file_name,
                    path=self.config_file_paths
                )
            except ConfigFileNotFound:
                # Only warn if the default config file was NOT being used.
                if config_file_name in self.config_file_specified:
                    msg = self.log.warning
                else:
                    msg = self.log.debug
                msg("Config file not found, skipping: %s", config_file_name)
            except Exception:
                # For testing purposes.
                if not suppress_errors:
                    raise
                self.log.warning("Error loading config file: %s" %
                              self.config_file_name, exc_info=True)

def launch_scheduler(in_addr, out_addr, mon_addr, not_addr, reg_addr, config=None,
                        logname='root', log_url=None, loglevel=logging.DEBUG,
                        identity=b'task', in_thread=False):

    ZMQStream = zmqstream.ZMQStream

    if config:
        # unwrap dict back into Config
        config = Config(config)

    if in_thread:
        # use instance() to get the same Context/Loop as our parent
        ctx = zmq.Context.instance()
        loop = ioloop.IOLoop.current()
    else:
        # in a process, don't use instance()
        # for safety with multiprocessing
        ctx = zmq.Context()
        loop = ioloop.IOLoop()
    ins = ZMQStream(ctx.socket(zmq.ROUTER),loop)
    util.set_hwm(ins, 0)
    ins.setsockopt(zmq.IDENTITY, identity + b'_in')
    ins.bind(in_addr)

    outs = ZMQStream(ctx.socket(zmq.ROUTER),loop)
    util.set_hwm(outs, 0)
    outs.setsockopt(zmq.IDENTITY, identity + b'_out')
    outs.bind(out_addr)
    mons = zmqstream.ZMQStream(ctx.socket(zmq.PUB),loop)
    util.set_hwm(mons, 0)
    mons.connect(mon_addr)
    nots = zmqstream.ZMQStream(ctx.socket(zmq.SUB),loop)
    nots.setsockopt(zmq.SUBSCRIBE, b'')
    nots.connect(not_addr)

    querys = ZMQStream(ctx.socket(zmq.DEALER),loop)
    querys.connect(reg_addr)

    # setup logging.
    if in_thread:
        log = Application.instance().log
    else:
        if log_url:
            log = connect_logger(logname, ctx, log_url, root="scheduler", loglevel=loglevel)
        else:
            log = local_logger(logname, loglevel)

    scheduler = TaskScheduler(client_stream=ins, engine_stream=outs,
                            mon_stream=mons, notifier_stream=nots,
                            query_stream=querys,
                            loop=loop, log=log,
                            config=config)
    scheduler.start()
    if not in_thread:
        try:
            loop.start()
        except KeyboardInterrupt:
            scheduler.log.critical("Interrupted, exiting...")

def load_default_config(ipython_dir=None):
    """Load the default config file from the default ipython_dir.

    This is useful for embedded shells.
    """
    if ipython_dir is None:
        ipython_dir = get_ipython_dir()

    profile_dir = os.path.join(ipython_dir, 'profile_default')

    config = Config()
    for cf in Application._load_config_files("ipython_config", path=profile_dir):
        config.update(cf)

    return config

    def is_interactive(self):
        """ Determine if the user requested interactive mode.
        """
        # The Python interpreter sets sys.flags correctly, so use them!
        if sys.flags.interactive:
            return True

        # IPython does not set sys.flags when -i is specified, so first
        # check it if it is already imported.
        if '__IPYTHON__' not in dir(six.moves.builtins):
            return False

        # Then we check the application singleton and determine based on
        # a variable it sets.
        try:
            try:
                # ipython >=3.0
                from traitlets.config.application import Application as App
            except ImportError:
                # ipython <3.0
                from IPython.config.application import Application as App
            return App.initialized() and App.instance().interact
        except (ImportError, AttributeError):
            return False

def get_app():
    return Application.instance()