code: def _lower_bound(value: Optional[float] = None) -> float:
      if value is None:
          return default_likelihood_positive_minimum()
      return value
  
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 1 for calling a global function with example usage: _lower_bound(value) and returns: value, default_likelihood_positive_minimum