Create words_finder.py

text = "bla PythoN foo python"
1) Find patterns: (PythoN, python)
2) Split initial text into parts by every case of pattern:
parts = ["bla , " foo "]
3) Create list with patterns:
entries = ["PythoN", "python"]
4) Wrap patterns into tags:
entries = ["<span>PythoN</span>", "<span>python</span>"]
5) Gather parts of text and entries together.