--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/setdefault	Thu Jan 30 09:58:26 2014 +0100
@@ -0,0 +1,19 @@
+**Fine:**
+{{{#!python
+score_list = [
+   ('alice', 5),
+   ('bob', 1),
+   ('bob', 3),
+   ('alice', 2),
+   ...
+]
+scores_by_name = {}
+for name, score in score_list:
+    scores_by_name[name] = scores_by_name.get(name, []).append(score)
+}}}
+
+**Better:**
+{{{#!python
+for name, score in score_list:
+    scores_by_name.setdefault(name, []).append(score)
+}}}
\ No newline at end of file