class_docstr: Implements `RateCurve` class using discounting function.
code: def get_discount_factor(self, interpolation_dates):
      return self._discount_fn(interpolation_dates)
  
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 2 for calling the RateCurveFromDiscountingFunction obj's underlying member method code with example usage: obj.get_discount_factor(interpolation_dates) and returns: self