diff -r 31342913fb1e Objects/abstract.c
--- a/Objects/abstract.c	Thu Feb 09 02:01:37 2017 +0100
+++ b/Objects/abstract.c	Thu Feb 09 19:31:33 2017 +0900
@@ -2745,13 +2745,12 @@ PyObject *
 }
 
 static PyObject *
-object_vacall(PyObject *callable, va_list vargs)
+object_vacall(PyObject *callable, PyObject *self, va_list vargs)
 {
     PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];
     PyObject **stack;
     Py_ssize_t nargs;
     PyObject *result;
-    Py_ssize_t i;
     va_list countva;
 
     if (callable == NULL) {
@@ -2760,7 +2759,7 @@ object_vacall(PyObject *callable, va_lis
 
     /* Count the number of arguments */
     va_copy(countva, vargs);
-    nargs = 0;
+    nargs = (self != NULL);
     while (1) {
         PyObject *arg = va_arg(countva, PyObject *);
         if (arg == NULL) {
@@ -2782,7 +2781,11 @@ object_vacall(PyObject *callable, va_lis
         }
     }
 
-    for (i = 0; i < nargs; ++i) {
+    Py_ssize_t i = 0;
+    if (self != NULL) {
+        stack[i++] = self;
+    }
+    for (; i < nargs; ++i) {
         stack[i] = va_arg(vargs, PyObject *);
     }
 
@@ -2795,23 +2798,32 @@ object_vacall(PyObject *callable, va_lis
     return result;
 }
 
+extern int
+_PyObject_GetMethod(PyObject *obj, PyObject *name, PyObject **method);
+
 PyObject *
-PyObject_CallMethodObjArgs(PyObject *callable, PyObject *name, ...)
+PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)
 {
     va_list vargs;
     PyObject *result;
 
-    if (callable == NULL || name == NULL) {
+    if (obj == NULL || name == NULL) {
         return null_error();
     }
 
-    callable = PyObject_GetAttr(callable, name);
+    PyObject *callable;
+    int meth_found = _PyObject_GetMethod(obj, name, &callable);
     if (callable == NULL) {
         return NULL;
     }
 
     va_start(vargs, name);
-    result = object_vacall(callable, vargs);
+    if (meth_found) {
+        result = object_vacall(callable, obj, vargs);
+    }
+    else {
+        result = object_vacall(callable, NULL, vargs);
+    }
     va_end(vargs);
 
     Py_DECREF(callable);
@@ -2829,13 +2841,19 @@ PyObject *
         return null_error();
     }
 
-    callable = _PyObject_GetAttrId(obj, name);
+    int meth_found = _PyObject_GetMethod(
+        obj, _PyUnicode_FromId(name), &callable);
     if (callable == NULL) {
         return NULL;
     }
 
     va_start(vargs, name);
-    result = object_vacall(callable, vargs);
+    if (meth_found) {
+        result = object_vacall(callable, obj, vargs);
+    }
+    else {
+        result = object_vacall(callable, NULL, vargs);
+    }
     va_end(vargs);
 
     Py_DECREF(callable);
@@ -2849,7 +2867,7 @@ PyObject_CallFunctionObjArgs(PyObject *c
     PyObject *result;
 
     va_start(vargs, callable);
-    result = object_vacall(callable, vargs);
+    result = object_vacall(callable, NULL, vargs);
     va_end(vargs);
 
     return result;
diff -r 31342913fb1e Objects/object.c
--- a/Objects/object.c	Thu Feb 09 02:01:37 2017 +0100
+++ b/Objects/object.c	Thu Feb 09 19:31:33 2017 +0900
@@ -785,7 +785,7 @@ PyObject_GetAttrString(PyObject *v, cons
 
     if (Py_TYPE(v)->tp_getattr != NULL)
         return (*Py_TYPE(v)->tp_getattr)(v, (char*)name);
-    w = PyUnicode_InternFromString(name);
+    w = PyUnicode_FromString(name);
     if (w == NULL)
         return NULL;
     res = PyObject_GetAttr(v, w);