# documentação Django 2.0.8

# Código fonte para django.urls.conf

    """Functions for use in URLsconfs."""
    from functools import partial
    from importlib import import_module

    from django.core.exceptions import ImproperlyConfigured

    from .resolvers import (
        LocalePrefixPattern, RegexPattern, RoutePattern, URLPattern, URLResolver,
    )

    def include(arg, namespace=None):
        app_name = None
        if isinstance(arg, tuple):
            # Callable returning a namespace hint.
            try:
                urlconf_module, app_name = arg
            except ValueError:
                if namespace:
                    raise ImproperlyConfigured(
                        'Cannot override the namespace for a dynamic module that '
                        'provides a namespace.'
                    )
                raise ImproperlyConfigured(
                    'Passing a %d-tuple to include() is not supported. Pass a '
                    '2-tuple containing the list of patterns and app_name, and '
                    'provide the namespace argument to include() instead.' % len(arg)
                )
        else:
            # No namespace hint - use manually provided namespace.
            urlconf_module = arg

        if isinstance(urlconf_module, str):
            urlconf_module = import_module(urlconf_module)
        patterns = getattr(urlconf_module, 'urlpatterns', urlconf_module)
        app_name = getattr(urlconf_module, 'app_name', app_name)
        if namespace and not app_name:
            raise ImproperlyConfigured(
                'Specifying a namespace in include() without providing an app_name '
                'is not supported. Set the app_name attribute in the included '
                'module, or pass a 2-tuple containing the list of patterns and '
                'app_name instead.',
            )
        namespace = namespace or app_name
        # Make sure the patterns can be iterated through (without this, some
        # testcases will break).
        if isinstance(patterns, (list, tuple)):
            for url_pattern in patterns:
                pattern = getattr(url_pattern, 'pattern', None)
                if isinstance(pattern, LocalePrefixPattern):
                    raise ImproperlyConfigured(
                        'Using i18n_patterns in an included URLconf is not allowed.'
                    )
        return (urlconf_module, app_name, namespace)

    def _path(route, view, kwargs=None, name=None, Pattern=None):
        if isinstance(view, (list, tuple)):
            # For include(...) processing.
            pattern = Pattern(route, is_endpoint=False)
            urlconf_module, app_name, namespace = view
            return URLResolver(
                pattern,
                urlconf_module,
                kwargs,
                app_name=app_name,
                namespace=namespace,
            )
        elif callable(view):
            pattern = Pattern(route, name=name, is_endpoint=True)
            return URLPattern(pattern, view, kwargs, name)
        else:
            raise TypeError('view must be a callable or a list/tuple in the case of include().')

    path = partial(_path, Pattern=RoutePattern)
    re_path = partial(_path, Pattern=RegexPattern)