(GameObject)Instantiate()

I have been practicing Unity around for 5 months

until now, about "Instantiate()" to instantiate GameObject,

usuallt the code was like this

"Instantiate(prefab, prefabPosition)"

but recently I have seen this kind of code

"(GameObject)Instantiate(prefab)"

I have read the unity document about this part but I can't understand

Please help me the meaning of those parenthesis in front to "Instantiate()"

 

It's called 'cast' or 'casting' and is an explicit conversion from one type to another.

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/types/casting-and-type-conversions
https://www.codeproject.com/Articles/447634/A-Beginners-Tutorial-Type-Casting-and-Type-Convers