only lint on py > 2

.travis.yml

@@ -3,6 +3,7 @@ sudo: required
 dist: trusty
 matrix:
   include:
+    - python: 2.7
     - python: 3.5
     - python: 3.6
 addons:
@@ -16,15 +17,15 @@ before_install:
   - export CC="gcc-4.9"
   - export CXX="g++-4.9"
 install:
-  - if [[ $TRAVIS_PYTHON_VERSION == 3.5 ]]; then pip install https://download.pytorch.org/whl/cpu/torch-1.1.0-cp35-cp35m-linux_x86_64.whl; fi
-  - if [[ $TRAVIS_PYTHON_VERSION == 3.6 ]]; then pip install https://download.pytorch.org/whl/cpu/torch-1.1.0-cp36-cp36m-linux_x86_64.whl; fi
+  - pip install numpy
+  - pip install torch_nightly -f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html
   - pip install pycodestyle
   - pip install flake8
   - pip install codecov
   - pip install torch-scatter
 script:
-  - pycodestyle .
-  - flake8 .
+  - if [[ $TRAVIS_PYTHON_VERSION != 2.7 ]]; then pycodestyle .; fi
+  - if [[ $TRAVIS_PYTHON_VERSION != 2.7 ]]; then flake8 .; fi
   - python setup.py install
   - python setup.py test
 after_success: