diff --git a/.gitignore b/.gitignore
index 9a220c6..1f543a6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+*.c
+*.html
 *.pyc
 *.swp
 *.so
diff --git a/AUTHORS.md b/AUTHORS.md
index 7a5c308..04bd230 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -2,4 +2,6 @@ Erik Welch                                      [@eriknw](https://github.com/eri
 
 [Matthew Rocklin](http://matthewrocklin.com)    [@mrocklin](http://github.com/mrocklin/)
 
+Lars Buitinck                                   [@larsmans](http://github.com/larsmans)
+
 [Thouis (Ray) Jones](http://people.seas.harvard.edu/~thouis)  [@thouis](https://github.com/thouis/)
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..69a668e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+PYTHON ?= python
+
+inplace:
+	$(PYTHON) setup.py build_ext --inplace
+
+test: inplace
+	nosetests -s --with-doctest cytoolz/
diff --git a/cytoolz/dicttoolz.pyx b/cytoolz/dicttoolz.pyx
index a807fe7..7c69e93 100644
--- a/cytoolz/dicttoolz.pyx
+++ b/cytoolz/dicttoolz.pyx
@@ -1,6 +1,7 @@
 #cython: embedsignature=True
 from cpython.dict cimport (PyDict_Check, PyDict_GetItem, PyDict_Merge,
-                           PyDict_New, PyDict_SetItem, PyDict_Update)
+                           PyDict_New, PyDict_Next, PyDict_SetItem,
+                           PyDict_Update)
 from cpython.exc cimport PyErr_Clear, PyErr_GivenExceptionMatches, PyErr_Occurred
 from cpython.list cimport PyList_Append, PyList_New
 from cpython.ref cimport PyObject
@@ -94,10 +95,19 @@ cpdef dict valmap(object func, dict d):
     See Also:
         keymap
     """
-    cdef dict rv
+    cdef:
+        dict rv
+        Py_ssize_t pos
+        PyObject *k
+        PyObject *v
+
+    if d is None:
+        raise TypeError("expected dict, got None")
+
     rv = PyDict_New()
-    for k, v in d.iteritems():
-       PyDict_SetItem(rv, k, func(v))
+    pos = 0
+    while PyDict_Next(d, &pos, &k, &v):
+       PyDict_SetItem(rv, <object>k, func(<object>v))
     return rv
 
 
@@ -112,10 +122,19 @@ cpdef dict keymap(object func, dict d):
     See Also:
         valmap
     """
-    cdef dict rv
+    cdef:
+        dict rv
+        Py_ssize_t pos
+        PyObject *k
+        PyObject *v
+
+    if d is None:
+        raise TypeError("expected dict, got None")
+
     rv = PyDict_New()
-    for k, v in d.iteritems():
-       PyDict_SetItem(rv, func(k), v)
+    pos = 0
+    while PyDict_Next(d, &pos, &k, &v):
+       PyDict_SetItem(rv, func(<object>k), <object>v)
     return rv
 
 
@@ -132,11 +151,20 @@ cpdef dict valfilter(object predicate, dict d):
         keyfilter
         valmap
     """
-    cdef dict rv
+    cdef:
+        dict rv
+        Py_ssize_t pos
+        PyObject *k
+        PyObject *v
+
+    if d is None:
+        raise TypeError("expected dict, got None")
+
     rv = PyDict_New()
-    for k, v in d.iteritems():
-        if predicate(v):
-            PyDict_SetItem(rv, k, v)
+    pos = 0
+    while PyDict_Next(d, &pos, &k, &v):
+        if predicate(<object>v):
+            PyDict_SetItem(rv, <object>k, <object>v)
     return rv
 
 
@@ -153,11 +181,20 @@ cpdef dict keyfilter(object predicate, dict d):
         valfilter
         keymap
     """
-    cdef dict rv
+    cdef:
+        dict rv
+        Py_ssize_t pos
+        PyObject *k
+        PyObject *v
+
+    if d is None:
+        raise TypeError("expected dict, got None")
+
     rv = PyDict_New()
-    for k, v in d.iteritems():
-        if predicate(k):
-            PyDict_SetItem(rv, k, v)
+    pos = 0
+    while PyDict_Next(d, &pos, &k, &v):
+        if predicate(<object>k):
+            PyDict_SetItem(rv, <object>k, <object>v)
     return rv
 
 
diff --git a/cytoolz/tests/test_none_safe.py b/cytoolz/tests/test_none_safe.py
index 4edfeb1..b65175d 100644
--- a/cytoolz/tests/test_none_safe.py
+++ b/cytoolz/tests/test_none_safe.py
@@ -53,15 +53,13 @@ def test_dicttoolz():
     tested.append('get_in')
 
     assert raises(TypeError, lambda: keyfilter(None, {1: 2}))
-    assert raises((TypeError, AttributeError),
-                  lambda: keyfilter(identity, None))
+    assert raises(TypeError, lambda: keyfilter(identity, None))
     tested.append('keyfilter')
 
     # XXX
     assert (raises(TypeError, lambda: keymap(None, {1: 2})) or
             keymap(None, {1: 2}) == {(1,): 2})
-    assert raises((TypeError, AttributeError),
-                  lambda: keymap(identity, None))
+    assert raises(TypeError, lambda: keymap(identity, None))
     tested.append('keymap')
 
     assert raises(TypeError, lambda: merge(None))
@@ -81,15 +79,13 @@ def test_dicttoolz():
     tested.append('update_in')
 
     assert raises(TypeError, lambda: valfilter(None, {1: 2}))
-    assert raises((TypeError, AttributeError),
-                  lambda: valfilter(identity, None))
+    assert raises(TypeError, lambda: valfilter(identity, None))
     tested.append('valfilter')
 
     # XXX
     assert (raises(TypeError, lambda: valmap(None, {1: 2})) or
             valmap(None, {1: 2}) == {1: (2,)})
-    assert raises((TypeError, AttributeError),
-                  lambda: valmap(identity, None))
+    assert raises(TypeError, lambda: valmap(identity, None))
     tested.append('valmap')
 
     s1 = set(tested)