This function doesn't appear to work at all. You have to create a new BCMath\Number object to use it, at which point it attempts to overwrite the value of said object - and of course that won't work because BCMath\Number::$value is readonly.
(PHP 8 >= 8.4.0)
BcMath\Number::__unserialize — Deserializa un argumento de datos en un objeto BcMath\Number
Deserializa un argumento de datos en un objeto BcMath\Number.
dataEste método lanza una ValueError si se pasan datos serializados inválidos.
This function doesn't appear to work at all. You have to create a new BCMath\Number object to use it, at which point it attempts to overwrite the value of said object - and of course that won't work because BCMath\Number::$value is readonly.