diff --git a/.style.yapf b/.style.yapf
new file mode 100644
index 0000000..3bd5017
--- /dev/null
+++ b/.style.yapf
@@ -0,0 +1,4 @@
+[style]
+COLUMN_LIMIT = 119
+INDENT_WIDTH = 4
+USE_TABS = False
diff --git a/.travis.yml b/.travis.yml
index c3d82fe..88760b6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,8 @@ cache:
   - pip
   - bundler
 install:
-- bundle install
+  - pip install -r requirements.txt
+  - bundle install
 script:
-- bundle exec danger
-- python hello_world.py
+  - bundle exec danger
+  - python hello_world.py
diff --git a/Gemfile.lock b/Gemfile.lock
index ee40883..faf0ad4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,6 +1,6 @@
 GIT
   remote: https://github.com/robertodr/danger-code_style_validation.git
-  revision: de63c3daee20a8611a6216ac35e77327eba5cd50
+  revision: 6978bba01500f30294aab14db9c36298979f7d5b
   branch: yapf
   specs:
     danger-code_style_validation (0.2.0)
diff --git a/hello_world.py b/hello_world.py
index 1464990..9001f3e 100644
--- a/hello_world.py
+++ b/hello_world.py
@@ -1,8 +1,15 @@
+def vector(dim):
+    import numpy as np
+
+
+    return np.random.rand(dim)
+
 def message():
     return 'Hello, Danger world!'
 
 def main():
     print(message())
+    print(vector(10))
 
 if __name__ == '__main__':
     main()
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..612ba38
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,2 @@
+yapf
+futures