Returns a unit, which is a base for include reference.
This method should be called when a node may potentially hbe defined in several units
at once (in case of expansion) and caller needs a unit, which is a base for this node's
include statement.
If this node has no include statement, return value of the method should be equal to the result of
unit() method call.
Returns a unit, which is a base for include reference. This method should be called when a node may potentially hbe defined in several units at once (in case of expansion) and caller needs a unit, which is a base for this node's include statement.
If this node has no include statement, return value of the method should be equal to the result of unit() method call.