class_docstr: Represents an interest rate curve.
code: def valuation_date(self):
      return self._valuation_date
  
file_path: tf-quant-finance/tf_quant_finance/experimental/instruments/rate_curve.py
imports: import tensorflow.compat.v2
  from tf_quant_finance import datetime
  from tf_quant_finance.math.interpolation import linear
label_desc: Use image node_id 5 for calling the RateCurve obj's underlying member method code with example usage: obj.valuation_date() and returns: self