In order to keep things nice and clean and in this case, simple, you might be better off using array_merge( )

I personally declare any arrays at the top of my class file, in order to make them globally accessible, only because I tend to keep methods free of array declaration (OCD I guess!)

So for me I have an example that might help you, it’s something that works for me when needed to add/merge two arrays together:

b

Bla bla