https://issues.apache.org/jira/browse/SPARK-4897 adds Python 3.4 support to 1.4.0 and above, but the official docs (1.4.1, but the same is for 1.4.0) says explicitly:
"Spark 1.4.1 works with Python 2.6 or higher (but not Python 3)."
There are some other Python-related things, which are outdated, e.g. this line:
"For example, to launch the IPython Notebook with PyLab plot support:"
(At least since IPython 3.0 PyLab/Matplotlib support happens inside a notebook; and the line "--pylab inline" is already removed.)