Merge pull request #1917 from takluyver/i1914

Fix for %pdef on Python 3

A nice simple one - types.InstanceType is for old style classes, so we don't check against it on Python 3.

closes  #1914

IPython/core/oinspect.py

@@ -354,7 +354,7 b' class Inspector:'
         if inspect.isclass(obj):
             header = self.__head('Class constructor information:\n')
             obj = obj.__init__
-        elif type(obj) is types.InstanceType:
+        elif (not py3compat.PY3) and type(obj) is types.InstanceType:
             obj = obj.__call__
 
         output = self._getdef(obj,oname)

IPython/core/tests/test_oinspect.py

@@ -283,3 +283,8 b' def test_getdoc():'
     nt.assert_equal(oinspect.getdoc(a), "standard docstring")
     nt.assert_equal(oinspect.getdoc(b), "custom docstring")
     nt.assert_equal(oinspect.getdoc(c), "standard docstring")
+
+def test_pdef():
+    # See gh-1914
+    def foo(): pass
+    inspector.pdef(foo, 'foo')