Refactor '_license_diff()' #29

  * Modified definitions of 'new_licenses' and 'old_licenses' to
    delete "or []" -- appears not to be needed.
  * Modified test for "license info added"/"license info removed"
    where relevant score(s) < 'cutoff_score'.

Signed-off-by: John M. Horan <johnmhoran@gmail.com>

Author: johnmhoran

src/deltacode/__init__.py

@@ -181,14 +181,13 @@ def _license_diff(self, cutoff_score=50):
         'license info removed', 'license info added' or 'license change' if
         there has been a license change and depending on the nature of that change.
         """
-        new_licenses = self.new_file.licenses or []
-        old_licenses = self.old_file.licenses or []
+        new_licenses = self.new_file.licenses
+        old_licenses = self.old_file.licenses
 
-        if len(new_licenses) != len(old_licenses):
-            if len(new_licenses) == 0:
-                self.category = 'license info removed'
-            elif len(old_licenses) == 0:
-                self.category = 'license info added'
+        if new_licenses and not old_licenses:
+            self.category = 'license info added'
+        if not new_licenses and old_licenses:
+            self.category = 'license info removed'
 
         new_keys = set(l.key for l in new_licenses if l.score >= cutoff_score)
         old_keys = set(l.key for l in old_licenses if l.score >= cutoff_score)