Deprecation warning due to invalid escape sequences.

[tirkarthi]

Issue Type

Please specify the type of the issue you want to submit:

• [x] Bug Report
• [ ] Feature Request
• [ ] Documentation Report
• [ ] General Enhancement Idea

Versions & Configuration

Please specify the following things:

• version of sure: master branch
• implementation and version of python: 3.8
• operating system: Ubuntu

Steps to reproduce (Expected and Actual Results)

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|doc|benchmark|tool' | xargs -P4 -I{} python3.8 -Wall -m py_compile {}
./tests/test_assertion_builder.py:547: DeprecationWarning: invalid escape sequence \w
  ("expect('some string').to.match(r'\w{4} \w{6}') matches regex")
./tests/test_assertion_builder.py:560: DeprecationWarning: invalid escape sequence \d
  "'some string' doesn't match the regular expression /\d{2} \d{4}/")

[gabrielfalcao]

thanks for the report @tirkarthi