[local_defined] returns True if a local variable has been defined in the current scope or False otherwise. Can be used to check if a local variable has been defined even if the current value of the local variable is Null or the empty string.

Note that this is entered for compatibility and is functionally equivalent to local(local_name)->isNotA(::null).

Please refer to the documentation for "isA" and "isNotA" for specific documentation.