examples: fix employee example

examples/tutorial/employee/employee.py

@@ -1,10 +1,10 @@
-#------------------------------------------------------------------------------
-# Copyright (c) 2013, Nucleic Development Team.
+# ------------------------------------------------------------------------------
+# Copyright (c) 2013-2023, Nucleic Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file LICENSE, distributed with this software.
-#------------------------------------------------------------------------------
+# ------------------------------------------------------------------------------
 from __future__ import print_function
 
 import datetime
@@ -14,12 +14,13 @@
 from enaml.qt.qt_application import QtApplication
 
 import sys, os
+
 sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 
+
 class Person(Atom):
-    """ A simple class representing a person object.
+    """A simple class representing a person object."""
 
-    """
     last_name = Str()
 
     first_name = Str()
@@ -30,48 +31,45 @@ class Person(Atom):
 
     debug = Bool(False)
 
-    @observe('age')
+    @observe("age")
     def debug_print(self, change):
-        """ Prints out a debug message whenever the person's age changes.
-
-        """
+        """Prints out a debug message whenever the person's age changes."""
         if self.debug:
             templ = "{first} {last} is {age} years old."
             s = templ.format(
-                first=self.first_name, last=self.last_name, age=self.age,
+                first=self.first_name,
+                last=self.last_name,
+                age=self.age,
             )
             print(s)
 
-    @observe('dob')
+    @observe("dob")
     def update_age(self, change):
-        """ Update the person's age whenever their date of birth changes
-
-        """
+        """Update the person's age whenever their date of birth changes"""
         # grab the current date time
-        now = datetime.datetime.now(datetime.UTC)
+        now = datetime.datetime.now()
         # estimate the person's age within one year accuracy
         age = now.year - self.dob.year
         # check to see if the current date is before their birthday and
         # subtract a year from their age if it is
-        if ((now.month == self.dob.month and now.day < self.dob.day)
-            or now.month < self.dob.month):
-                age -= 1
+        if (
+            now.month == self.dob.month and now.day < self.dob.day
+        ) or now.month < self.dob.month:
+            age -= 1
         # set the persons age
         self.age = age
 
 
 class Employer(Person):
-    """ An employer is a person who runs a company.
+    """An employer is a person who runs a company."""
 
-    """
     # The name of the company
     company_name = Str()
 
 
 class Employee(Person):
-    """ An employee is person with a boss and a phone number.
+    """An employee is person with a boss and a phone number."""
 
-    """
     # The employee's boss
     boss = Value(Employer)
 
@@ -81,16 +79,20 @@ class Employee(Person):
     # This method will be called automatically by atom when the
     # employee's phone number changes
     def _observe_phone(self, val):
-        print('received new phone number for %s: %s' % (self.first_name, val))
+        print("received new phone number for %s: %s" % (self.first_name, val))
 
 
 def main():
     # Create an employee with a boss
     boss_john = Employer(
-        first_name='John', last_name='Paw', company_name="Packrat's Cats",
+        first_name="John",
+        last_name="Paw",
+        company_name="Packrat's Cats",
     )
     employee_mary = Employee(
-        first_name='Mary', last_name='Sue', boss=boss_john,
+        first_name="Mary",
+        last_name="Sue",
+        boss=boss_john,
         phone=(555, 555, 5555),
     )
 
@@ -105,5 +107,6 @@ def main():
 
     app.start()
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     main()