diff -r bf5a899a5d7c Lib/inspect.py
--- a/Lib/inspect.py	Sun Apr 12 17:56:34 2015 -0400
+++ b/Lib/inspect.py	Tue Apr 14 18:41:10 2015 -0400
@@ -596,7 +596,7 @@
             if hasattr(object, '__file__'):
                 return object.__file__
         raise TypeError('{!r} is a built-in class'.format(object))
-    if ismethod(object):
+    while ismethod(object):
         object = object.__func__
     if isfunction(object):
         object = object.__code__
@@ -772,7 +772,7 @@
         else:
             raise OSError('could not find class definition')
 
-    if ismethod(object):
+    while ismethod(object):
         object = object.__func__
     if isfunction(object):
         object = object.__code__
diff -r bf5a899a5d7c Lib/test/test_inspect.py
--- a/Lib/test/test_inspect.py	Sun Apr 12 17:56:34 2015 -0400
+++ b/Lib/test/test_inspect.py	Tue Apr 14 18:41:10 2015 -0400
@@ -339,6 +339,18 @@
         self.assertSourceEqual(git.abuse, 29, 39)
         self.assertSourceEqual(mod.StupidGit, 21, 50)
 
+    def test_getsource_nested_methodtype(self):
+        """
+        Note: MethodType is not intended to be used for methods, but if it
+        is used on methods, getsource should still locate the source. Refer
+        to Issue 19956 (http://bugs.python.org/issue19956)
+        """
+        m1 = types.MethodType((lambda self: self), object())
+        m2 = types.MethodType(m1, object())
+        source1 = inspect.getsource(m1)
+        source2 = inspect.getsource(m2)
+        self.assertEqual(source1, source2)
+
     def test_getsourcefile(self):
         self.assertEqual(normcase(inspect.getsourcefile(mod.spam)), modfile)
         self.assertEqual(normcase(inspect.getsourcefile(git.abuse)), modfile)
@@ -353,7 +365,7 @@
 
     def test_getfile(self):
         self.assertEqual(inspect.getfile(mod.StupidGit), mod.__file__)
-
+            
     def test_getfile_class_without_module(self):
         class CM(type):
             @property
@@ -364,6 +376,13 @@
         with self.assertRaises(TypeError):
             inspect.getfile(C)
 
+    def test_getfile_nested_methodtype(self):
+        m1 = types.MethodType((lambda self: self), object())
+        m2 = types.MethodType(m1, object())
+        source1 = inspect.getfile(m1)
+        source2 = inspect.getfile(m2)
+        self.assertEqual(source1, source2)
+
     def test_getmodule_recursion(self):
         from types import ModuleType
         name = '__inspect_dummy'
@@ -497,6 +516,13 @@
             self.assertRaises(IOError, inspect.findsource, co)
             self.assertRaises(IOError, inspect.getsource, co)
 
+    def test_findsource_nested_methodtype(self):
+        m1 = types.MethodType((lambda self: self), object())
+        m2 = types.MethodType(m1, object())
+        source1 = inspect.findsource(m1)
+        source2 = inspect.findsource(m2)
+        self.assertEqual(source1, source2)
+
 class TestNoEOL(GetSourceBase):
     def __init__(self, *args, **kwargs):
         self.tempdir = TESTFN + '_dir'