Deprecation warning due to invalid escape sequences

[tirkarthi]

Deprecation warning due to invalid escape sequences. Using raw strings or escaping them again helps in resolving this. Check https://github.com/asottile/pyupgrade/ for automatic fix of this.

find . -iname '*.py' | grep -Ev 'rdf4|tool|doc' | xargs -P4 -I{} python3.8 -Wall -m py_compile {}
./test/benchmark.py:112: DeprecationWarning: invalid escape sequence \|
  self._spinner = itertools.cycle('-\|/')