--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/duck%20typing	Wed Jan 29 19:55:01 2014 +0100
@@ -0,0 +1,18 @@
+**Wrong:**
+{{{#!python
+if not isinstance(parameter, list):
+    raise TypeError("Please provide a list.")
+}}}
+
+**Better:**
+{{{#!python
+iter(parameter)
+}}}
+
+**Fine:**
+{{{#!python
+import collections
+
+if not isinstance(parameter, collections.iterable):
+    raise TypeError("Please provide an interable.")
+}}}
\ No newline at end of file