Ref Keys

Key Ref Keys of function Price in Tradable refers to a text that defines the key associated with the parameter that is being set to a specific value before the evaluation takes place.
It must be one of the keys contained in the object specified in Ref Objects, the value of which must be a number, boolean, date or object of type
If more than one objects are specified in Ref Objects, then an array of corresponding keys is expected here.

This entry may even specify the keys contained in sub-objects, which sub-objects are contained in the specified objects.
In that case, this entry must have the form of a two-dimensional array, where the iᵗʰ column supplies the keys that define the inclusion path associated with the iᵗʰ object.
In the simple case with several supplied objects and without the involvement of sub-objects, the keys that correspond to the supplied objects must be supplied as a single row.

As an example, assume the Ref Objects entry is an array with the two elements hnd1, hnd2 representing the handle names of two objects.
Then the entry here must be a - generally - two-dimensional array with two columns, with the first column corresponding to the object hnd1 and the second column corresponding to the object hnd2
Each of these two columns may contain just one cell or several cells, depending on the type of key being chosen as part of the respective object.
The simplest case is when the key of the object hnd1 is part of the outer layer of hnd1, i.e. not part of any of the sub-objects of hnd1 and similarly for the key of the object hnd2
Assume the first such key is named KeyOuter1 and the second is named KeyOuter2
Then the one-dimensional array will appear in Excel as a range with two columns and one row, as follows:
KeyOuter1 KeyOuter2
Consider now the slightly more complex case when the value associated with the key KeyOuter2 is itself an object, effectively a sub-object of hnd2
In this case, it may happen that the hnd2-associated variable that needs to be referred here is part of that sub-object and is associated with the key KeyDeeper2 of that sub-object.
Then this variable is effectively identified through the path of keys KeyOuter2 -> KeyDeeper2
It turns out, a two-dimensional array is needed, where the second column must consist of two cells containing these two keys.
Then the two-dimensional array will appear in Excel as a range with two rows and two columns with the bottom/left cell being blank, as follows:
KeyOuter1 KeyOuter2

More details concerning the sub-objects case are available at
Ref Key