How to use the pyhocon.exceptions.ConfigMissingException function in pyhocon

def test_configtree_pop(self):
        config_tree = ConfigTree()
        config_tree.put("string", "string")
        assert config_tree.pop("string", "default") == "string"
        assert config_tree.pop("string-new", "default") == "default"
        assert config_tree == ConfigTree()

        with pytest.raises(ConfigMissingException):
            assert config_tree.pop("string-new")

        config_tree.put("list", [1, 2, 3])
        assert config_tree.pop("list", [4]) == [1, 2, 3]
        assert config_tree.pop("list-new", [4]) == [4]
        assert config_tree == ConfigTree()

        config_tree.put("config", {'a': 5})
        assert config_tree.pop("config", {'b': 1}) == {'a': 5}
        assert config_tree.pop("config-new", {'b': 1}) == {'b': 1}
        assert config_tree == ConfigTree()

        config_tree = ConfigTree()
        config_tree.put('key', 'value')
        assert config_tree.pop('key', 'value') == 'value'
        assert 'key' not in config_tree

}
}
www.example-ö.com {
    us {
        name = "second domain"
    }
}
        """

        config = ConfigFactory.parse_string(input_string)

        assert config.get_string(u'www.sample.com.us.name') == 'first domain'
        assert config.get_string(u'www.example-ö.com.us.name') == 'second domain'
        with pytest.raises(ConfigWrongTypeException):
            config.put(u'www.example-ö', 'append_failure', append=True)
        with pytest.raises(ConfigMissingException):
            config.get_string(u'missing_unicode_key_ö')
        with pytest.raises(ConfigException):
            config.get_bool(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigException):
            config.get_list(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigException):
            config.get_config(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigWrongTypeException):
            config.get_string(u'www.example-ö.com.us.name.missing')

}
}
www.example-ö.com {
    us {
        name = "second domain"
    }
}
        """

        config = ConfigFactory.parse_string(input_string)

        assert config.get_string(u'www.sample.com.us.name') == 'first domain'
        assert config.get_string(u'www.example-ö.com.us.name') == 'second domain'
        with pytest.raises(ConfigWrongTypeException):
            config.put(u'www.example-ö', 'append_failure', append=True)
        with pytest.raises(ConfigMissingException):
            config.get_string(u'missing_unicode_key_ö')
        with pytest.raises(ConfigException):
            config.get_bool(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigException):
            config.get_list(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigException):
            config.get_config(u'www.example-ö.com.us.name')
        with pytest.raises(ConfigWrongTypeException):
            config.get_string(u'www.example-ö.com.us.name.missing')

def test_missing_config(self):
        config = ConfigFactory.parse_string(
            """
            a = 5
            """
        )
        # b is not set so show raise an exception
        with pytest.raises(ConfigMissingException):
            config.get('b')

def test_missing_config(self):
        config = ConfigFactory.parse_string(
            """
            a = 5
            """
        )
        # b is not set so show raise an exception
        with pytest.raises(ConfigMissingException):
            config.get('b')

def _resolve_variable(cls, config, substitution):
        """
        :param config:
        :param substitution:
        :return: (is_resolved, resolved_variable)
        """
        variable = substitution.variable
        try:
            return True, config.get(variable)
        except ConfigMissingException:
            # default to environment variable
            value = os.environ.get(variable)

            if value is None:
                if substitution.optional:
                    return False, None
                else:
                    raise ConfigSubstitutionException(
                        "Cannot resolve variable ${{{variable}}} (line: {line}, col: {col})".format(
                            variable=variable,
                            line=lineno(substitution.loc, substitution.instring),
                            col=col(substitution.loc, substitution.instring)))
            elif isinstance(value, ConfigList) or isinstance(value, ConfigTree):
                raise ConfigSubstitutionException(
                    "Cannot substitute variable ${{{variable}}} because it does not point to a "
                    "string, int, float, boolean or null {type} (line:{line}, col: {col})".format(

def _get(self, key_path, key_index=0, default=UndefinedKey):
        key_elt = key_path[key_index]
        elt = super(ConfigTree, self).get(key_elt, UndefinedKey)

        if elt is UndefinedKey:
            if default is UndefinedKey:
                raise ConfigMissingException(u"No configuration setting found for key {key}".format(key='.'.join(key_path[:key_index + 1])))
            else:
                return default

        if key_index == len(key_path) - 1:
            if isinstance(elt, NoneValue):
                return None
            elif isinstance(elt, list):
                return [None if isinstance(x, NoneValue) else x for x in elt]
            else:
                return elt
        elif isinstance(elt, ConfigTree):
            return elt._get(key_path, key_index + 1, default)
        else:
            if default is UndefinedKey:
                raise ConfigWrongTypeException(
                    u"{key} has type {type} rather than dict".format(key='.'.join(key_path[:key_index + 1]),