code: def db_handler(args):
      
  
      if args.type == 'create':
          if args.db is None:
              db.init_db()
          return
  
      if not db.setup(url=args.db, echo=args.db_echo):
          return
  
      if args.type == 'status':
          current_rev = db_revision.current_db_revision()
          print('The current DB schema version:', current_rev)
  
      if args.type == 'upgrade':
          db.upgrade()
  
      if args.type == 'revision':
          db_revision.new_revision()
  
      if args.type == 'drop':
          if args.db is not None:
              db.downgrade()
          db.remove_db()
docs: db_handler.