How to Execute Oracle stored procedures at will

Currently, we have couple stored procedures in Liquibase that should only be called when the schema is empty.  How should we set this up correctly?

Option 1:  commented out the calls whenever we need to run liquibase in a non-empty schema (so that the test_create_data will not populate data again)?
I have tried this way, but it failed.  It would give me ‘Build failure’ error.

        call test_create_synonyms();
        call test_create_data();

Option 2: change any parameter setting? which one?

Thanks for your input!