class_docstr: A naming scheme using the dundered name syntax.
  
  TODO: Consolidate with StructuredLinkableSpecName / DunderedNameFormatter.
class_docstr_tok: ["A","naming","scheme","using","the","dundered","name","syntax",".","TODO",":","Consolidate","with","StructuredLinkableSpecName","\/","DunderedNameFormatter","."]
code: def input_str(self, instance_spec: InstanceSpec) -> Optional[str]:
      spec_set = InstanceSpecSet.from_specs((instance_spec,))
  
      for time_dimension_spec in spec_set.time_dimension_specs:
          # From existing comment in StructuredLinkableSpecName:
          #
          # Dunder syntax not supported for querying date_part
          #
          if time_dimension_spec.date_part is not None:
              return None
      names = _DunderNameTransform().transform(spec_set)
      if len(names) != 1:
          raise RuntimeError(
              f"Did not get 1 name for {instance_spec}. Got {names}"
          )
  
      return names[0]
  
imports: from __future__ import annotations
  import re
  from typing import Optional, Sequence, Tuple
  from dbt_semantic_interfaces.naming.keywords import DUNDER
  from dbt_semantic_interfaces.references import EntityReference
  from dbt_semantic_interfaces.type_enums import TimeGranularity
  from dbt_semantic_interfaces.type_enums.date_part import DatePart
  from typing_extensions import override
  from metricflow.naming.naming_scheme import QueryItemNamingScheme
  from metricflow.specs.patterns.entity_link_pattern import EntityLinkPattern, EntityLinkPatternParameterSet, ParameterSetField
  from metricflow.specs.specs import InstanceSpec, InstanceSpecSet, InstanceSpecSetTransform
label_desc: Use image node_id 2 for calling the DunderNamingScheme obj's underlying member method code with example usage: obj.input_str(instance_spec) and returns: names, None