code: def to_list(x):
      """Converts input to a list if necessary."""
      if isinstance(x, (list, tuple)):
          return x
      else:
          return [x]
  
imports: from typing import Optional, Tuple, Callable, Any, List, Union
  import numpy
  import tensorflow.compat.v2
  from tf_quant_finance import datetime
  from tf_quant_finance.experimental.pricing_platform.framework.core import curve_types
  from tf_quant_finance.experimental.pricing_platform.framework.core import processed_market_data
  from tf_quant_finance.experimental.pricing_platform.framework.core import types
  from tf_quant_finance.experimental.pricing_platform.framework.market_data import rate_curve
  from tf_quant_finance.experimental.pricing_platform.framework.market_data import utils
  from tf_quant_finance.experimental.pricing_platform.framework.rate_instruments import coupon_specs
  from tf_quant_finance.experimental.pricing_platform.instrument_protos import period_pb2
  from tf_quant_finance.math import pad
label_desc: Use image node_id 6 for calling a global function with example usage: to_list(x) and returns: x, list