Ensure implementation of reverse relations in 'fields' is backwards compatible

1 files changed, 1 insertions, 1 deletions

diff --git a/rest_framework/permissions.py b/rest_framework/permissions.py
index ae895f39..2aa45c71 100644
--- a/rest_framework/permissions.py
+++ b/rest_framework/permissions.py
@@ -25,7 +25,7 @@ class BasePermission(object):
         """
         Return `True` if permission is granted, `False` otherwise.
         """
-        if len(inspect.getargspec(self.has_permission)[0]) == 4:
+        if len(inspect.getargspec(self.has_permission).args) == 4:
             warnings.warn('The `obj` argument in `has_permission` is due to be deprecated. '
                       'Use `has_object_permission()` instead for object permissions.',
                        PendingDeprecationWarning, stacklevel=2)