@observe('age')
    def debug_print(self, change):
        if self.debug:
            templ = "{first} {last} is {age} years old."
            s = templ.format(
                first=self.first_name, last=self.last_name, age=self.age,
            )
            print s
Prints out a debug message whenever the person's age changes.
dataset/ETHPy150Open ContinuumIO/ashiba/enaml/examples/tutorial/person/person.py/Person.debug_print