How do you reference an enumeration in a trigger guard?

[mse]

For an activity diagram simulation, what is the proper notation for referencing an enumeration? Should it be:

"Enum1"

or

'Enum1'

or

Enum1

The EA documentation says that quotation marks are used for strings, but this is for an enumeration.

If I use Enum1, there is an error because it is not recognized. If I use ", then it treats it like a string. The ' also treats it like a string.