fixed issue#73 and added a test

1 files changed, 6 insertions, 4 deletions

diff --git a/djangorestframework/serializer.py b/djangorestframework/serializer.py
index 4e1c6b80..43d32b29 100644
--- a/djangorestframework/serializer.py
+++ b/djangorestframework/serializer.py
@@ -230,12 +230,14 @@ class Serializer(object):
         # serialize each required field
         for fname in fields:
             try:
-                if inspect.ismethod(getattr(self, fname, None)) and \
-                        len(inspect.getargspec(getattr(self, fname))[0]) == 2:
-                    # check first for a method 'fname' on self first
+                # we first check for a method 'fname' on self,
+                # 'fname's signature must be 'def fname(self, instance)'
+                meth = getattr(self, fname, None)
+                if (inspect.ismethod(meth) and
+                            len(inspect.getargspec(meth)[0]) == 2):
                     obj = meth(instance)
                 elif hasattr(instance, '__contains__') and fname in instance:
-                    # check for a key 'fname' on the instance
+                    # then check for a key 'fname' on the instance
                     obj = instance[fname]
                 elif hasattr(instance, smart_str(fname)):
                     # finally check for an attribute 'fname' on the instance