Perhaps you should try some spelling variations:
string functions » scoring functions (Expand search), strange functions (Expand search), sorting functions (Expand search)
coverage string » coverage during (Expand search), average string (Expand search), coverage nursing (Expand search)
python python » pythons python (Expand search), pitons python (Expand search), pytm python (Expand search)
and coverage » and cover (Expand search)
piton python » pitons python (Expand search), in python (Expand search), with python (Expand search)
coder and » code and (Expand search), codes and (Expand search), poder and (Expand search)
api piton » api python (Expand search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( coder and coverage string functions ) OR ( api piton python python programming ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( coder AND coverage string functions ) OR ( api piton python python programming )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( coder and coverage string functions ) OR ( api piton python python programming ))".
• Adding a wildcard symbol may retrieve word variants: (( coder and coverage string functions ) OR ( api piton python python programming ))*.