set_value(an_object, a_label, a_value)
Set a value in a record or a property of a script object with specifying its label of a text.
if an_object does not have a_label, a_label is added into a_object when an_object is a record. When an_object is a script object, passing nonexistent label cause an error.
If new label is added into an_object, returned value is not same instance to an_object.
record or script object : usually same to an_object