Merge 14c22bcab3 into 4ff9e96b4c

rest_framework/compat.py

@@ -140,6 +140,16 @@ def value_from_object(field, obj):
     return field.value_from_object(obj)
 
 
+def getargspec(obj):
+    if not hasattr(inspect, 'signature'):  # Python 2.7 - 3.2
+        parameters, _, _, defaults = inspect.getargspec(obj)
+    else:  # Python +3.3
+        signature = inspect.signature(obj)
+        parameters = signature.parameters
+        defaults = [i for i in parameters if i.default != inspect._empty]
+
+    return parameters, defaults
+
 # contrib.postgres only supported from 1.8 onwards.
 try:
     from django.contrib.postgres import fields as postgres_fields

rest_framework/fields.py

@@ -32,7 +32,8 @@ from django.utils.translation import ugettext_lazy as _
 
 from rest_framework import ISO_8601
 from rest_framework.compat import (
-    get_remote_field, unicode_repr, unicode_to_repr, value_from_object
+    get_remote_field, getargspec, unicode_repr, unicode_to_repr,
+    value_from_object
 )
 from rest_framework.exceptions import ValidationError
 from rest_framework.settings import api_settings
@@ -59,8 +60,9 @@ def is_simple_callable(obj):
     if not (function or method):
         return False
 
-    args, _, _, defaults = inspect.getargspec(obj)
-    len_args = len(args) if function else len(args) - 1
+    parameters, defaults = getargspec(obj)
+
+    len_args = len(parameters) if function else len(parameters) - 1
     len_defaults = len(defaults) if defaults else 0
     return len_args <= len_defaults