pip与pip3在Heroku上部署Django应用程序

Question

我想在将python从2.7升级到3.4后，在Heroku上重新部署django应用程序。当我（重新） - 当地运行

$pip3 install -r requirements.txt

我得到了

Requirement already satisfied (use --upgrade to upgrade): Brlapi==0.6.1 in /usr/lib/python3/dist-packages (from -r requirements.txt (line 1))

然而，当我在Heroku上推送应用程序时，我得到了

remote: -----> Python app detected
remote: -----> Installing python-3.4.3
remote:      $ pip install -r requirements.txt
remote:        Collecting Brlapi==0.6.1 (from -r requirements.txt (line 1))
remote:          Could not find a version that satisfies the requirement  Brlapi==0.6.1 (from -r requirements.txt (line 1)) (from versions: )
remote:        No matching distribution found for Brlapi==0.6.1 (from -r requirements.txt (line 1))

请注意，我在runtime.txt文件中指定了python（3.4.3）的版本。我怀疑这个问题来自于Heroku正在运行pip而不是pip3。你能告诉我这是不是问题，如果是的话，我如何让Heroku运行pip3，如果不是，请给我一些关于我应该调查的地方的提示？谢谢。