code: def downgrades(src):
      
      def _(f):
          destination = src - 1
  
          @do(operator.setitem(_downgrade_methods, destination))
          @wraps(f)
          def wrapper(op, conn, version_info_table):
              conn.execute(version_info_table.delete())  # clear the version
              f(op)
              write_version_info(conn, version_info_table, destination)
  
          return wrapper
      return _
docs: Decorator for marking that a method is a downgrade to a version to the
      previous version.
  
      Parameters
      ----------
      src : int
          The version this downgrades from.
  
      Returns
      -------
      decorator : callable[(callable) -> callable]
          The decorator to apply.