Try travis config like it is in deeptools

.travis.yml

@@ -1,16 +1,14 @@
 language: python
 sudo: true
-services:
-  - postgresql
+#services:
+# - postgresql
 # addons:
 #   apt:
 #     packages:
 #     - samtools
-python:
-  - 2.7
-  - 3.5 # [no osx] 
-  - 3.6
-
+env:
+  - TRAVIS_PYTHON_VERSION=2.7
+  - TRAVIS_PYTHON_VERSION=3.6
 os:
   - linux
   - osx
@@ -20,6 +18,7 @@ jobs:
     - stage: lint
       env:
         - LINT=1
+        - TRAVIS_PYTHON_VERSION=2.7
       before_install:
         - curl https://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh -o miniconda.sh
         - bash miniconda.sh -b -p $HOME/miniconda
@@ -38,7 +37,6 @@ before_install:
   - export HIC_TEST_DATA_DIR="`pwd`/hicexplorer/test/test_data/"
   - echo $HIC_TEST_DATA_DIR
   - if [[ "$TRAVIS_OS_NAME" == "linux" && "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then curl https://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh -o miniconda.sh ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" && "$TRAVIS_PYTHON_VERSION" == "3.5" ]]; then curl https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -o miniconda.sh ; fi
   - if [[ "$TRAVIS_OS_NAME" == "linux" && "$TRAVIS_PYTHON_VERSION" == "3.6" ]]; then curl https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -o miniconda.sh ; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" && "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then curl https://repo.continuum.io/miniconda/Miniconda2-latest-MacOSX-x86_64.sh -o miniconda.sh ; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" && "$TRAVIS_PYTHON_VERSION" == "3.6" ]]; then curl https://repo.continuum.io/miniconda/Miniconda3-latest-MacOSX-x86_64.sh -o miniconda.sh ; fi