Perhaps you should try some spelling variations:
"code code coverage riemann problem" » "code code coverage region problem" (Expand search), "code code coverage human problem" (Expand search), "code care coverage riemann problem" (Expand search), "code and coverage riemann problem" (Expand search), "code the coverage riemann problem" (Expand search), "code cdc coverage riemann problem" (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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"code code coverage riemann problem\") OR (\"api python python python programming\"))~".
• Removing quotes may allow a broader search: (( code code coverage riemann problem ) OR ( api python python python programming ))~.
• Adding a wildcard symbol may retrieve word variants: (("code code coverage riemann problem") OR ("api python python python programming"))*.