code: def _validate_param(self, expected, param):
          
          ok, msg = self.contract.validate(expected, expected.is_array, param)
          if not ok:
              vals = (self.full_name, expected.name, msg)
              msg = "Function '%s' invalid param '%s'. %s" % vals
              raise RpcException(ERR_INVALID_PARAMS, msg)
docs: Validates a single param against its expected type.
          Raises RpcException if the param is invalid
          
          :Parameters:
            expected
              Type instance
            param
              Parameter value to validate