On the page for rule G-8510 (https://trivadis.github.io/plsql-and-sql-coding-guidelines/4-language-usage/8-patterns/4-ensure-single-execution-at-a-time-of-a-program-unit/g-8410/)
the example-code is incomplete:

• in the code-window "Example (bad)" is the code for the package used in the code-window "Example (good)"

• therefore a bad code-example is missing