diff --git a/waybackpy/cli.py b/waybackpy/cli.py
index c043b23..08aa1a6 100644
--- a/waybackpy/cli.py
+++ b/waybackpy/cli.py
@@ -95,8 +95,9 @@ def _save_urls_on_file(input_list, live_url_count):
     if m:
         domain = m.group(1)
 
+    sys_random = random.SystemRandom()
     uid = "".join(
-        random.choice(string.ascii_lowercase + string.digits) for _ in range(6)
+        sys_random.choice(string.ascii_lowercase + string.digits) for _ in range(6)
     )
 
     file_name = "{domain}-{live_url_count}-urls-{uid}.txt".format(
diff --git a/waybackpy/utils.py b/waybackpy/utils.py
index d94e594..ed122fb 100644
--- a/waybackpy/utils.py
+++ b/waybackpy/utils.py
@@ -123,11 +123,11 @@ def _check_filters(filters):
         raise WaybackError("filters must be a list.")
 
     # [!]field:regex
-    for filter in filters:
+    for _filter in filters:
         try:
             match = re.search(
                 r"(\!?(?:urlkey|timestamp|original|mimetype|statuscode|digest|length)):(.*)",
-                filter,
+                _filter,
             )
 
             key = match.group(1)
@@ -135,8 +135,8 @@ def _check_filters(filters):
 
         except Exception:
             exc_message = (
-                "Filter '{filter}' not following the cdx filter syntax.".format(
-                    filter=filter
+                "Filter '{_filter}' not following the cdx filter syntax.".format(
+                    _filter=_filter
                 )
             )
             raise WaybackError(exc_message)
@@ -267,7 +267,7 @@ def _archive_url_parser(header, url, latest_version=__version__, instance=None):
         newest_archive = None
         try:
             newest_archive = instance.newest()
-        except Exception as e:
+        except WaybackError:
             pass  # We don't care as this is a save request
 
         if newest_archive:
diff --git a/waybackpy/wrapper.py b/waybackpy/wrapper.py
index c8f7e60..8e13d09 100644
--- a/waybackpy/wrapper.py
+++ b/waybackpy/wrapper.py
@@ -1,5 +1,3 @@
-import requests
-import concurrent.futures
 from datetime import datetime, timedelta
 from .exceptions import WaybackError
 from .cdx import Cdx