Load our settings file.

def load_settings_file(self, settings_file=None):
        """
        Load our settings file.
        """

        if not settings_file:
            settings_file = self.get_json_or_yaml_settings()
        if not os.path.isfile(settings_file):
            raise ClickException("Please configure your zappa_settings file or call `zappa init`.")

        path, ext = os.path.splitext(settings_file)
        if ext == '.yml' or ext == '.yaml':
            with open(settings_file) as yaml_file:
                try:
                    self.zappa_settings = yaml.load(yaml_file)
                except ValueError: # pragma: no cover
                    raise ValueError("Unable to load the Zappa settings YAML. It may be malformed.")
        elif ext == '.toml':
            with open(settings_file) as toml_file:
                try:
                    self.zappa_settings = toml.load(toml_file)
                except ValueError: # pragma: no cover
                    raise ValueError("Unable to load the Zappa settings TOML. It may be malformed.")
        else:
            with open(settings_file) as json_file:
                try:
                    self.zappa_settings = json.load(json_file)
                except ValueError: # pragma: no cover
                    raise ValueError("Unable to load the Zappa settings JSON. It may be malformed.")