language: python
python:
  - "2.7"
  - "3.4"
  - "3.5"
  - "3.6"
  - "3.7"
    dist: xenial
    sudo: true
  - "pypy"
services: mongodb
install:
  - "pip install -r requirements.txt"
script: "python test.py"

language: python
python:
  - "2.7"
  - "3.4"
  - "3.5"
  - "3.6"
  - "pypy"
matrix:
  include:
    - python: 3.7
      dist: xenial
      sudo: true
services: mongodb
install:
  - "pip install -r requirements.txt"
script: "python test.py"

Use 3.7 version as separated matrix.
Use 3.7 version as separated matrix.
