code: def _check_currency(currency: str):
      """Check that currency is in supported set."""
      if currency not in currency_set:
          raise ValueError(
              f"currency {currency} not in supported currency set, "
              f"{currency_set}"
          )
  
file_path: pyjanitor/janitor/finance.py
imports: import json
  from datetime import date
  from functools import lru_cache
  from typing import Optional
  import pandas
  import pandas_flavor
  import requests
  from janitor.errors import JanitorError
  from .utils import check, deprecated_alias, is_connected
label_desc: Use image node_id 1 for calling a global function with example usage: _check_currency(currency) without return types