1237.lean:9:4-9:15: warning: declaration uses `sorry`
1237.lean:9:4-9:15: warning: declaration uses `sorry`
1237.lean:9:4-9:15: warning: declaration uses `sorry`
1237.lean:9:4-9:15: warning: declaration uses `sorry`
1237.lean:9:4-9:15: warning: declaration uses `sorry`