As a point of comparison, an approximation (ie. untested, probably some syntax errors) of the corresponding Ansible tasks:

    - apt: name={{ item }}
      with_items:
        - postgresql-server
        - nginx
    - pip: name={{ item }}
      with_items:
        - flask
        - peewee
    - copy: src=nginx/static dest=/www/ recurse=yes
    - copy: src=nginx/sites_enabled dest=/etc/nginx/ recurse=yes
    - service: name=postgresql state=running enabled=yes
    - service: name=nginx state=running enabled=yes
    - postgresql_user: name=foo password=oof priv=table1,table2
    - file: path=/usr/src/app state=directory
    - copy: src=app.py dest=/usr/src/app/app.py
    - copy: src=templates dest=/usr/src/app/ recurse=yes
    - copy: src=python_app.conf dest=/etc/init/
    - service: name=python_app state=started enabled=yes

Implementation note: this uses an init file for the python app, which will depend upon what OS and init system you're running it under. Also missing handlers for restarting services when config files change.