code: def checked_combined_branch(self) -> BaseOutput:  # noqa: D
      assert self.combined_branch is not None
      return self.combined_branch
  
imports: from __future__ import annotations
  import logging
  from dataclasses import dataclass
  from typing import List, Optional, Sequence
  from metricflow.dataflow.dataflow_plan import AddGeneratedUuidColumnNode, AggregateMeasuresNode, BaseOutput, CombineAggregatedOutputsNode, ComputeMetricsNode, ConstrainTimeRangeNode, DataflowPlanNode, DataflowPlanNodeVisitor, FilterElementsNode, JoinConversionEventsNode, JoinOverTimeRangeNode, JoinToBaseOutputNode, JoinToTimeSpineNode, MetricTimeDimensionTransformNode, MinMaxNode, OrderByLimitNode, ReadSqlSourceNode, SemiAdditiveJoinNode, WhereConstraintNode, WriteToResultDataframeNode, WriteToResultTableNode
  from metricflow.dataflow.optimizer.source_scan.matching_linkable_specs import MatchingLinkableSpecsTransform
  from metricflow.specs.specs import MetricSpec
label_desc: Use image node_id 2 for calling the ComputeMetricsBranchCombinerResult obj's underlying member method code with example usage: obj.checked_combined_branch() and returns: self