docs: def _compile_control_flow_expression(self,
                                           expr: Expression,
                                           scope: Dict[str, TensorFluent],
                                           batch_size: Optional[int] = None,
                                           noise: Optional[List[tf.Tensor]] = None) -> TensorFluent:
          '''Compile a control flow expression `expr` into a TensorFluent
          in the given `scope` with optional batch size.
  
          Args:
              expr (:obj:`rddl2tf.expr.Expression`): A RDDL control flow expression.
              scope (Dict[str, :obj:`rddl2tf.fluent.TensorFluent`]): A fluent scope.
              batch_size (Optional[size]): The batch size.
  
          Returns:
              :obj:`rddl2tf.fluent.TensorFluent`: The compiled expression as a TensorFluent.
          '''
          etype = expr.etype
          args = expr.args
          if etype[1] == 'if':
              condition = self._compile_expression(args[0], scope, batch_size, noise)
              true_case = self._compile_expression(args[1], scope, batch_size, noise)
              false_case = self._compile_expression(args[2], scope, batch_size, noise)
              fluent = TensorFluent.if_then_else(condition, true_case, false_case)
          else:
              raise ValueError('Invalid control flow expression:\n{}'.format(expr))
          return fluent