diff --git a/nodebook/nodebookcore.py b/nodebook/nodebookcore.py
index 98b5cdc..ddae374 100644
--- a/nodebook/nodebookcore.py
+++ b/nodebook/nodebookcore.py
@@ -46,6 +46,9 @@ class ReferenceFinder(ast.NodeVisitor):
         self.locals.add(node.name)
         self.generic_visit(node)
 
+    def visit_arg(self, node):
+        self.locals.add(node.arg)
+
     def visit_AugAssign(self, node):
         target = node.target
         while (type(target) is ast.Subscript):
diff --git a/setup.py b/setup.py
index 11d6a77..adc7229 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@ import sys
 
 setup(
     name='nodebook',
-    version='0.2.0',
+    version='0.2.1',
     author='Kevin Zielnicki',
     author_email='kzielnicki@stitchfix.com',
     license='Stitch Fix 2017',

diff --git a/tests/test_nodebookcore.py b/tests/test_nodebookcore.py
index cfd9646..470121c 100644
--- a/tests/test_nodebookcore.py
+++ b/tests/test_nodebookcore.py
@@ -42,6 +42,16 @@ class TestReferenceFinder(object):
         assert rf.locals == {'pd', 'y'}
         assert rf.imports == {'pandas'}
 
+    def test_function(self, rf):
+        code_tree = ast.parse(
+            "def add(x,y):\n"
+            "    return x+y\n"
+        )
+        rf.visit(code_tree)
+        assert rf.inputs == set()
+        assert rf.locals == {'add', 'x', 'y'}
+        assert rf.imports == set()
+
 
 class TestNodebook(object):
     @pytest.fixture()
diff --git a/tests/test_pickledict.py b/tests/test_pickledict.py
index ef35fdd..90b7088 100644
--- a/tests/test_pickledict.py
+++ b/tests/test_pickledict.py
@@ -33,6 +33,12 @@ class TestPickleDict(object):
         df = pd.DataFrame({'a': [0, 1, 2], 'b': ['foo', 'bar', 'baz']})
         mydict['test_df'] = df
         assert mydict['test_df'].equals(df)
+        
+    def test_func(self, mydict):
+        def add(a, b):
+            return a + b
+        mydict['test_func'] = add
+        assert mydict['test_func'](3,5) == 8
 
     def test_immutability(self, mydict):
         l = [1, 2, 3]

Functions don't work in nodebook in py3
Because of changes to the ast in Python 3, functions no longer are parsed correctly. Eg, from @hacktuarial:
```
def add(a, b):
    return a + b
```
nodebook throws an error:
```
KeyError: "name 'a' is not defined"
```
tests/test_nodebookcore.py::TestReferenceFinder::test_function
tests/test_nodebookcore.py::TestReferenceFinder::test_assign tests/test_nodebookcore.py::TestReferenceFinder::test_augassign tests/test_nodebookcore.py::TestReferenceFinder::test_import tests/test_nodebookcore.py::TestReferenceFinder::test_multiline tests/test_nodebookcore.py::TestNodebook::test_single_node tests/test_nodebookcore.py::TestNodebook::test_node_chain tests/test_pickledict.py::TestPickleDict::test_int[mode_memory] tests/test_pickledict.py::TestPickleDict::test_int[mode_disk] tests/test_pickledict.py::TestPickleDict::test_string[mode_memory] tests/test_pickledict.py::TestPickleDict::test_string[mode_disk] tests/test_pickledict.py::TestPickleDict::test_bytes[mode_memory] tests/test_pickledict.py::TestPickleDict::test_bytes[mode_disk] tests/test_pickledict.py::TestPickleDict::test_df[mode_memory] tests/test_pickledict.py::TestPickleDict::test_df[mode_disk] tests/test_pickledict.py::TestPickleDict::test_func[mode_memory] tests/test_pickledict.py::TestPickleDict::test_func[mode_disk] tests/test_pickledict.py::TestPickleDict::test_immutability[mode_memory] tests/test_pickledict.py::TestPickleDict::test_immutability[mode_disk]