How to deal with"No Parameter Found By that name"

[Yna_Db]

See this thread:

How do you write Type Parameters? - Family Symbol node error

It seems simple - but how on earth do you write to a type parameter? I have wall type, I want to write to its parameters. Surely this is possible. Wading my way through possible ways to do it I came across errors in FamilySymbol.Family and Family.Symbols nodes. They look like a coding error: [TypeParameters]