On pypi.python.org, the pyspark package is tagged with version 2.2.0.post0: https://pypi.python.org/pypi/pyspark/2.2.0
However, when you install the package, it has version 2.2.0.
This has really annoying consequences: if you try pip install pyspark==2.2.0, it won't work. Instead you have to do pip install pyspark==2.2.0.post0. Then, if you later run the same command (pip install pyspark==2.2.0.post0), it won't recognize the existing pyspark installation (because it has version 2.2.0) and instead will reinstall it, which is very slow because pyspark is a large package.
This can happen if you add a new package to a requirements.txt file; you end up waiting a lot longer than necessary because every time you run pip install -r requirements.txt it reinstalls pyspark.
Can you please change the package on PyPi to have the version 2.2.0?