diff --git a/async_crawler.py b/async_crawler.py
index f8285ad..2dae874 100644
--- a/async_crawler.py
+++ b/async_crawler.py
@@ -24,6 +24,15 @@ from utils.helpers import RobotsTxt, AsyncCrawler, standardise_url
 def sanity_checks(url=None):
     '''
     Runs some basic sanity checks before the crawler is initialised.
+
+    Accepts:
+      url: the root URL to be crawled.
+
+    Returns:
+      baseurl: a validated and cleaned version of the initial URL.
+              (type=string)
+      robots: an object which allows us to query whether a site may be crawled.
+              (type=RobotsTxt)
     '''
     # ensure we have a sensible URL to work with
     baseurl = standardise_url(url=url)
@@ -41,6 +50,11 @@ def sanity_checks(url=None):
 def render_sitemap(base_url=None, crawled_urls=None, runtime=None):
     '''
     Renders the sitemap to an HTML file.
+
+    Accepts:
+        base_url:
+        crawled_urls:
+        runtime:
     '''
     urlcount = len(crawled_urls)
     sorted_urls = sorted(crawled_urls)
diff --git a/utils/helpers.py b/utils/helpers.py
index 5739b7f..58770be 100644
--- a/utils/helpers.py
+++ b/utils/helpers.py
@@ -58,7 +58,7 @@ class AsyncCrawler(object):
         async with self.semaphore:
             async with self.client_session.head(url, timeout=5) as head:
                 try:
-                    data = await head.read()
+                    _ = await head.read()
                 except Exception as e:
                     print(e)
             if 'text/html' in head.headers['Content-Type']:
@@ -130,7 +130,7 @@ class AsyncCrawler(object):
         print('Crawling: {0}'.format(self.baseurl))
         while len(to_crawl) > 0:
             discovered_urls = await self.run(urls=to_crawl)
-            # empty toe crawl list and then add all newly discovered URLs for
+            # empty to_crawl list and then add all newly discovered URLs for
             # the next iteration.
             to_crawl.clear()
             to_crawl.extend(discovered_urls)