human
Complete this python program:
def build_pages(config, dump_json=False, dirty=False):
assistant
#Here is the Python code you requested.

    """Builds all the pages and writes them into the build directory.
    """
    site_navigation = nav.SiteNavigation(config[u'pages'], config[u'use_directory_urls'])
    loader = jinja2.FileSystemLoader((config[u'theme_dir'] + [config[u'mkdocs_templates']]))
    env = jinja2.Environment(loader=loader)
    from jinja2.runtime import Context
    deprecated_vars = {u'page_title': u'page.title', u'content': u'page.content', u'toc': u'page.toc', u'meta': u'page.meta', u'canonical_url': u'page.canonical_url', u'previous_page': u'page.previous_page', u'next_page': u'page.next_page', u'current_page': u'page', u'include_nav': u'nav|length>1', u'include_next_prev': u'(page.next_page    or    page.previous_page)', u'site_name': u'config.site_name', u'site_author': u'config.site_author', u'page_description': u'config.site_description', u'repo_url': u'config.repo_url', u'repo_name': u'config.repo_name', u'site_url': u'config.site_url', u'copyright': u'config.copyright', u'google_analytics': u'config.google_analytics', u'homepage_url': u'nav.homepage.url', u'favicon': u'{{    base_url    }}/img/favicon.ico'}
    class DeprecationContext(Context, ):
        def resolve(self, key):
            u'    Log    a    warning    when    accessing    any    deprecated    variable    name.    '
            if (key in deprecated_vars):
                log.warn(u"Template    variable    warning:    '{0}'    is    being    deprecated    and    will    not    be    available    in    a    future    version.    Use    '{1}'    instead.".format(key, deprecated_vars[key]))
            return super(DeprecationContext, self).resolve(key)
    env.context_class = DeprecationContext
    env.filters[u'tojson'] = filters.tojson
    search_index = search.SearchIndex()
    site_navigation.url_context.force_abs_urls = True
    default_base = site_navigation.url_context.base_path
    site_navigation.url_context.base_path = utils.urlparse(config[u'site_url']).path
    build_template(u'404.html', env, config, site_navigation)
    site_navigation.url_context.force_abs_urls = False
    site_navigation.url_context.base_path =...