diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..24218f9
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,10 @@
+language: python
+python:
+  - "3.6.6"
+# command to install dependencies
+install:
+  - pip install -r requirements-dev.txt
+# command to run tests
+script:
+  - flake8 sdiff tests
+  - nosetests
diff --git a/CHANGELOG b/CHANGELOG
index c2ff4bd..fc0b2a9 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,8 @@
+0.2.0 (2018-08-21)
+------------------
+
+- Upgrade to python 3.6
+
 0.1.3 (2015-08-13)
 ------------------
 
diff --git a/Makefile b/Makefile
index bbaf14a..734960f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,7 @@
 # Some simple testing tasks (sorry, UNIX only).
 
 PYTHON=venv/bin/python3
-PSERVE=venv/bin/gunicorn --paste
 PIP=venv/bin/pip
-EI=venv/bin/easy_install
 NOSE=venv/bin/nosetests
 FLAKE=venv/bin/flake8
 FLAGS=
@@ -21,7 +19,7 @@ install:
 	$(PYTHON) ./setup.py install
 
 flake:
-	$(FLAKE) event_pipe tests
+	$(FLAKE) sdiff tests
 
 test: flake
 	$(NOSE) -s $(FLAGS)
@@ -29,9 +27,6 @@ test: flake
 vtest:
 	$(NOSE) -s -v $(FLAGS)
 
-testloop:
-	while sleep 1; do $(NOSE) -s $(FLAGS); done
-
 cov cover coverage:
 	$(NOSE) -s --with-cover --cover-html --cover-html-dir ./coverage $(FLAGS)
 	echo "open file://`pwd`/coverage/index.html"
diff --git a/docs/.DS_Store b/docs/.DS_Store
deleted file mode 100644
index 5008ddf..0000000
Binary files a/docs/.DS_Store and /dev/null differ
diff --git a/sdiff/__init__.py b/sdiff/__init__.py
index fdb2986..3835f9c 100644
--- a/sdiff/__init__.py
+++ b/sdiff/__init__.py
@@ -1,6 +1,6 @@
 from .parser import parse
 from .renderer import TextRenderer
-from .compare import diff_struct, diff_links
+from .compare import diff_struct, diff_links  # noqa
 
 
 def diff(md1, md2, renderer=TextRenderer()):
diff --git a/sdiff/compare.py b/sdiff/compare.py
index ace1ae7..5958ada 100644
--- a/sdiff/compare.py
+++ b/sdiff/compare.py
@@ -1,12 +1,10 @@
-import re
 import logging
 from difflib import SequenceMatcher
 from itertools import zip_longest
 
-from .parser import parse
-from .tree_utils import traverse
 from .errors import DeleteError, InsertError
 from .model import Text
+from .tree_utils import traverse
 
 logger = logging.getLogger(__name__)
 
diff --git a/sdiff/parser.py b/sdiff/parser.py
index fa222a8..6a1e1c9 100644
--- a/sdiff/parser.py
+++ b/sdiff/parser.py
@@ -36,7 +36,6 @@ def parse_reflink(self, m):
 
     def _process_link(self, m):
         line = m.group(0)
-        text = m.group(1)
         if line[0] == '!':
             node = Image(line)
         else:
@@ -89,7 +88,6 @@ def parse_newline(self, m):
 
     def parse_heading(self, m):
         level = len(m.group(1))
-        text = m.group(0)
         node = Header(level)
         node.add_nodes(self._parse_inline(m.group(2)))
         self.tokens.append(node)
@@ -146,7 +144,7 @@ def _process_list_item(self, cap, bull):
                 pattern = re.compile(r'^ {1,%d}' % space, flags=re.M)
                 item = pattern.sub('', item)
 
-            # determin whether item is loose or not
+            # determine whether item is loose or not
             loose = _next
             if not loose and re.search(r'\n\n(?!\s*$)', item):
                 loose = True
diff --git a/sdiff/tree_utils.py b/sdiff/tree_utils.py
index 168a273..3bdb9a9 100644
--- a/sdiff/tree_utils.py
+++ b/sdiff/tree_utils.py
@@ -19,5 +19,7 @@ def traverse(tree, include_symbols=None, exclude_symbols=None):
             continue
         yield node
         previous = node
-        children = reversed(list(filter(lambda i: _ignore_node(i, include_symbols, exclude_symbols), node.nodes)))
+
+        child_list = [i for i in node.nodes if _ignore_node(i, include_symbols, exclude_symbols)]
+        children = reversed(child_list)
         stack.extendleft(children)
diff --git a/setup.py b/setup.py
index 391bd2f..341372d 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup, find_packages
 
 
-version = '0.2.2'
+version = '0.3.0'
 
 
 def read(f):
@@ -28,5 +28,5 @@ def read(f):
       packages=find_packages(exclude=['tests']),
       package_data={},
       namespace_packages=[],
-      install_requires = install_requires,
-      include_package_data = False)
+      install_requires=install_requires,
+      include_package_data=False)