Perhaps you should try some spelling variations:
"code using mixed regression testing" » "code using mixed regression kriging" (Expand search), "code using and regression testing" (Expand search), "made using mixed regression testing" (Expand search), "coding using mixed regression testing" (Expand search)
"api python python python programming" » "api pythons python python programming" (Expand search), "api piton python python programming" (Expand search), "api pitons python python programming" (Expand search), "rpa python python python programming" (Expand search), "manim python python python programming" (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: (("code using mixed regression testing") OR ("api python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"code using mixed regression testing\") OR (\"api python python python programming\"))".
• Removing quotes may allow a broader search: (( code using mixed regression testing ) OR ( api python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("code using mixed regression testing") OR ("api python python python programming"))*.