code: def _del_param(metric_obj, name):
      """Validate a new parameter value in a created metric object."""
      if name not in metric_obj._valid_params:
          raise ValueError(
              "Metric {} doesn't have a parameter {}.".format(
                  metric_obj.__name__, name
              )
          )
      if metric_obj._is_mandatory_param[name]:
          raise ValueError(
              "Parameter {} is mandatory, cannot reset.".format(name)
          )
      value = metric_obj._valid_params[name]
      setattr(metric_obj, "_" + name, value)
  
imports: from functools import partial
  import numpy
  from .None import _catboost
label_desc: Use image node_id 3 for calling a global function with example usage: _del_param(metric_obj, name) without return types