code: def _validate_input_source_against_placeholders(
      source: llmfn_inputs_source.LLMFnInputsSource,
      placeholders: AbstractSet[str],
  ) -> None:
      for inputs in source.to_normalized_inputs():
          for keyword in placeholders:
              if keyword not in inputs:
                  raise ValueError(
                      'Placeholder "{}" not found in input'.format(
                          keyword
                      )
                  )
  
imports: from __future__ import annotations
  import argparse
  import shlex
  import sys
  from typing import AbstractSet, Any, Callable, MutableMapping, Sequence
  from google.generativeai.notebook import argument_parser
  from google.generativeai.notebook import flag_def
  from google.generativeai.notebook import input_utils
  from google.generativeai.notebook import model_registry
  from google.generativeai.notebook import output_utils
  from google.generativeai.notebook import parsed_args_lib
  from google.generativeai.notebook import post_process_utils
  from google.generativeai.notebook import py_utils
  from google.generativeai.notebook import sheets_utils
  from google.generativeai.notebook.lib import llm_function
  from google.generativeai.notebook.lib import llmfn_inputs_source
  from google.generativeai.notebook.lib import llmfn_outputs
  from google.generativeai.notebook.lib import model
label_desc: Use image node_id 1 for calling a global function with example usage: _validate_input_source_against_placeholders(source, placeholders) without return types