Thinking more...

前幾天上傳程式到 openshift 時，發現新版的 six 安裝不上去，原因是 OpenShift 所帶的 six 是 0.3 版，但是無法透過 sudo 等之類的方式來安裝新版，所以想查到底是哪個模組會需要用到新版的 six。上網找了一下，發現 pipdeptree 可以滿足我的需求。
用 pip install pipdeptree 就可以安裝，使用上也很簡單，輸入 pipdeptree 就會列出各個模組的相依性與其所需最低版本。
結果大致是這樣：

Warning!!! Possibly conflicting dependencies found:
* HaodooScraper-Flask==1.0
 - python-dateutil [required: ==2.3, installed: 2.6.0]
 - six [required: ==1.3.0, installed: 1.10.0]
------------------------------------------------------------------------
alembic==0.6.7
  - Mako [required: Any, installed: 1.0.0]
    - MarkupSafe [required: >=0.9.2, installed: 0.23]
  - SQLAlchemy [required: >=0.7.3, installed: 0.9.8]
cssselect==0.9.1
Flask-APIBlueprint==1.0.0
  - flask [required: >=0.11.1,<1 -="" .0="" 0.12="" click="" installed:="" required:="">=2.0, installed: 6.7]
    - itsdangerous [required: >=0.21, installed: 0.24]
    - Jinja2 [required: >=2.4, installed: 2.9.5]
      - MarkupSafe [required: >=0.23, installed: 0.23]
    - Werkzeug [required: >=0.7, installed: 0.12.1]
  - six [required: <2 .0="">=1.10.0, installed: 1.10.0]
HaodooScraper-Flask==1.0
  - Flask [required: Any, installed: 0.12]
    - click [required: >=2.0, installed: 6.7]
    - itsdangerous [required: >=0.21, installed: 0.24]
    - Jinja2 [required: >=2.4, installed: 2.9.5]
      - MarkupSafe [required: >=0.23, installed: 0.23]
    - Werkzeug [required: >=0.7, installed: 0.12.1]
  - Flask-Bootstrap [required: Any, installed: 3.3.7.1]
    - dominate [required: Any, installed: 2.3.1]
    - Flask [required: >=0.8, installed: 0.12]
      - click [required: >=2.0, installed: 6.7]
      - itsdangerous [required: >=0.21, installed: 0.24]
      - Jinja2 [required: >=2.4, installed: 2.9.5]
        - MarkupSafe [required: >=0.23, installed: 0.23]
      - Werkzeug [required: >=0.7, installed: 0.12.1]
    - visitor [required: Any, installed: 0.1.3]
  - Flask-JsonTools [required: Any, installed: 0.1.1.post0]
    - flask [required: >=0.10.1, installed: 0.12]
      - click [required: >=2.0, installed: 6.7]
      - itsdangerous [required: >=0.21, installed: 0.24]
      - Jinja2 [required: >=2.4, installed: 2.9.5]
        - MarkupSafe [required: >=0.23, installed: 0.23]
      - Werkzeug [required: >=0.7, installed: 0.12.1]
  - flask-restplus [required: Any, installed: 0.10.1]
    - aniso8601 [required: >=0.82, installed: 1.2.0]
      - python-dateutil [required: Any, installed: 2.6.0]
        - six [required: >=1.5, installed: 1.10.0]
    - Flask [required: >=0.8, installed: 0.12]
      - click [required: >=2.0, installed: 6.7]
      - itsdangerous [required: >=0.21, installed: 0.24]
      - Jinja2 [required: >=2.4, installed: 2.9.5]
        - MarkupSafe [required: >=0.23, installed: 0.23]
      - Werkzeug [required: >=0.7, installed: 0.12.1]
    - jsonschema [required: Any, installed: 2.6.0]
    - pytz [required: Any, installed: 2017.2]
    - six [required: >=1.3.0, installed: 1.10.0]
  - Flask-WTF [required: Any, installed: 0.14.2]
    - Flask [required: Any, installed: 0.12]
      - click [required: >=2.0, installed: 6.7]
      - itsdangerous [required: >=0.21, installed: 0.24]
      - Jinja2 [required: >=2.4, installed: 2.9.5]
        - MarkupSafe [required: >=0.23, installed: 0.23]
      - Werkzeug [required: >=0.7, installed: 0.12.1]
    - WTForms [required: Any, installed: 2.1]
  - lxml [required: Any, installed: 3.4.0]
  - python-dateutil [required: ==2.3, installed: 2.6.0]
    - six [required: >=1.5, installed: 1.10.0]
  - requests [required: Any, installed: 2.13.0]
  - six [required: ==1.3.0, installed: 1.10.0]
  - SQLAlchemy [required: Any, installed: 0.9.8]
nose==1.2.1
pipdeptree==0.10.1
  - pip [required: >=6.0.0, installed: 9.0.1]
pkg-resources==0.0.0
PyMySQL==0.6.2
pyOpenSSL==0.14
  - cryptography [required: >=0.2.1, installed: 1.8.1]
    - asn1crypto [required: >=0.21.0, installed: 0.22.0]
    - cffi [required: >=1.4.1, installed: 1.10.0]
      - pycparser [required: Any, installed: 2.17]
    - idna [required: >=2.1, installed: 2.5]
    - packaging [required: Any, installed: 16.8]
      - pyparsing [required: Any, installed: 2.2.0]
      - six [required: Any, installed: 1.10.0]
    - setuptools [required: >=11.3, installed: 34.3.3]
      - appdirs [required: >=1.4.0, installed: 1.4.3]
      - packaging [required: >=16.8, installed: 16.8]
        - pyparsing [required: Any, installed: 2.2.0]
        - six [required: Any, installed: 1.10.0]
      - six [required: >=1.6.0, installed: 1.10.0]
    - six [required: >=1.4.1, installed: 1.10.0]
  - six [required: >=1.5.2, installed: 1.10.0]
wheel==0.30.0a0