docs: def current(self):
          """
          Display the current database revision
          """
  
          config = self.alembic_config()
          script = ScriptDirectory.from_config(config)
  
          revision = 'base'
  
          def display_version(rev, context):
              for rev in script.get_all_current(rev):
                  nonlocal revision
                  revision = rev.cmd_format(False)
  
              return []
  
          with EnvironmentContext(config, script, fn=display_version):
              script.run_env()
  
          return revision