diff --git a/renderspec/versions.py b/renderspec/versions.py
index 30c6098..b7d888b 100644
--- a/renderspec/versions.py
+++ b/renderspec/versions.py
@@ -24,13 +24,13 @@ def get_requirements(lines):
     """parse the given lines and return a dict with pkg_name->version.
     lines must follow PEP0508"""
     requires = {}
-    for l in lines:
+    for line in lines:
         # skip comments and empty lines
-        if l.startswith('#') or len(l.strip()) == 0:
+        if line.startswith('#') or len(line.strip()) == 0:
             continue
         # remove trailing comments
-        l = l.split('#')[0].rstrip(' ')
-        r = Requirement(l)
+        line = line.split('#')[0].rstrip(' ')
+        r = Requirement(line)
         # check if we need the requirement
         if r.marker:
             # TODO (toabctl): currently we hardcode python 2.7 and linux2
diff --git a/test-requirements.txt b/test-requirements.txt
index 9dd2f8e..c0a4dc9 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,7 +1,7 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-flake8<2.6.0,>=2.5.4 # MIT
+flake8>=3.5.0 # MIT
 testrepository>=0.0.18 # Apache-2.0/BSD
 testresources>=2.0.0 # Apache-2.0/BSD
 testtools>=1.4.0 # MIT