code: def get_combiner_descriptions():
      """This function returns a dictionary of combiner descriptions available at the type selection.
  
      The process works as follows - 1) Get a dictionary of valid combiners from the combiner config registry,
      but inverse the key/value pairs since we need to index `valid_combiners` later with an altered version
      of the combiner config class name. 2) Loop through Combiner Metadata entries, if a metadata entry has a
      combiner name that matches a valid combiner, add the description metadata to the output dictionary.
  
      Returns:
          dict: A dictionary of combiner descriptions.
      """
      return {
          k: convert_metadata_to_json(v[TYPE])
          for k, v in COMBINER_METADATA.items()
          if k in combiner_config_registry
      }
  
file_path: ludwig/ludwig/schema/combiners/utils.py
imports: from typing import Any, Dict, List, Type
  from ludwig.api_annotations import DeveloperAPI
  from ludwig.constants import TYPE
  from ludwig.schema import utils
  from ludwig.schema.combiners.base import BaseCombinerConfig
  from ludwig.schema.metadata import COMBINER_METADATA
  from ludwig.schema.metadata.parameter_metadata import convert_metadata_to_json, ParameterMetadata
  from ludwig.utils.registry import Registry
label_desc: Use image node_id 4 for calling a global function with example usage: get_combiner_descriptions() and returns: unknown