defaultValue: Anything - (Optional, default Nothing) default param (used when param is missing or of wrong type).
You can overload default value by declaring variable BIS_fnc_<functionName>_<index> in Namespace where BIS_fnc_param is called from. BIS_fnc_paramIn is a variant of the function with overloading disabled.
dataTypes: Array - (Optional, default Anything) list of allowed type examples (e.g. ["",[],0,objNull])
requiredCount: Number or Array - (Optional) if value is Array, checks if it has required number of elements