code: def _get_task_required_inputs(
      self, task_config: Union[RecTaskInfo, List[RecTaskInfo]]
  ) -> Set[str]:
      if isinstance(task_config, list):
          raise RecMetricException(
              "Session metric can only take one task at a time"
          )
  
      if task_config.session_metric_def is None:
          raise RecMetricException(
              "Please, specify the session metric definition"
          )
  
      return (
          {task_config.session_metric_def.session_var_name}
          if task_config.session_metric_def.session_var_name
          else set()
      )
  
imports: import logging
  from typing import Any, cast, Dict, List, Optional, Set, Type, Union
  import torch
  from torch import distributed
  from torchrec.metrics.metrics_config import RecTaskInfo, SessionMetricDef
  from torchrec.metrics.metrics_namespace import MetricName, MetricNamespace, MetricPrefix
  from torchrec.metrics.rec_metric import MetricComputationReport, RecComputeMode, RecMetric, RecMetricComputation, RecMetricException
label_desc: Use image node_id 3 for calling the RecallSessionMetric obj's underlying member method code with example usage: obj._get_task_required_inputs(task_config) and returns: unknown