Perhaps you should try some spelling variations:
variable functions » covariance functions (Expand search), variation functions (Expand search), measurable functions (Expand search)
functions problem » functions problems (Expand search), function problems (Expand search), functional problems (Expand search)
coding variable » cooking variables (Expand search), loading variables (Expand search), voiding variables (Expand search)
python python » pythons python (Expand search), piton python (Expand search), pytm python (Expand search)
coder coding » modern coding (Expand search), color coding (Expand search), odor coding (Expand search)
pitons » citons (Expand search), pitoni (Expand search), pitoes (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 coding variable functions problem ) OR ( api pitons python python programming ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( coder coding variable functions problem ) OR ( api pitons python python programming ))".
• Adding a wildcard symbol may retrieve word variants: (( coder coding variable functions problem ) OR ( api pitons python python programming ))*.