Perhaps you should try some spelling variations:
"period optimization python python programming" » "method optimization python python programming" (Expand search), "operation optimization python python programming" (Expand search), "hybrid optimization python python programming" (Expand search), "period optimization method python programming" (Expand search), "period optimization option python programming" (Expand search), "period optimization methods python programming" (Expand search), "period optimization pythons python programming" (Expand search), "period optimization piton python programming" (Expand search), "period optimization pitons python programming" (Expand search)
"coder detecting code coding program" » "model detecting code coding program" (Expand search), "code detection code coding program" (Expand search), "hole detecting code coding program" (Expand search), "coder detecting and coding program" (Expand search), "coder detecting code cloning program" (Expand search), "coder detecting code loading program" (Expand search), "coder detecting code cooling programs" (Expand search), "coder detecting code codigo program" (Expand search), "coder detecting code according program" (Expand search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder detecting code coding program\") OR (\"period optimization python python programming\"))~".
• Removing quotes may allow a broader search: (( coder detecting code coding program ) OR ( period optimization python python programming ))~.
• Adding a wildcard symbol may retrieve word variants: (("coder detecting code coding program") OR ("period optimization python python programming"))*.