code: def _scalar_log_prob(
      self, X: TensorType, F: TensorType, Y: TensorType
  ) -> tf.Tensor:
      return logdensities.exponential(Y, self.invlink(F))
  
imports: from math import sqrt
  from typing import Any, Callable, Optional
  import numpy
  import tensorflow
  from check_shapes import check_shapes, inherit_check_shapes
  from ..None import logdensities
  from ..base import MeanAndVariance, TensorType
  from ..config import default_likelihood_positive_minimum
  from ..utilities.parameter_or_function import ConstantOrFunction, ParameterOrFunction, evaluate_parameter_or_function, prepare_parameter_or_function
  from .base import ScalarLikelihood
  from .utils import inv_probit
label_desc: Use image node_id 2 for calling the Exponential obj's underlying member method code with example usage: obj._scalar_log_prob(X, F, Y) and returns: logdensities