updated contents from Atlas repo

objects/haunted_bus.py

@@ -0,0 +1,47 @@
+"""
+>>> bus1 = HountedBus(['Alice', 'Bill'])
+>>> bus1.passengers
+['Alice', 'Bill']
+>>> bus1.pick('Charlie')
+>>> bus1.drop('Alice')
+>>> bus1.passengers
+['Bill', 'Charlie']
+>>> bus2 = HountedBus()
+>>> bus2.pick('Carrie')
+>>> bus2.passengers
+['Carrie']
+>>> bus3 = HountedBus()
+>>> bus3.passengers
+['Carrie']
+>>> bus3.pick('Dave')
+>>> bus2.passengers
+['Carrie', 'Dave']
+>>> bus2.passengers is bus3.passengers
+True
+>>> bus1.passengers
+['Bill', 'Charlie']
+
+
+>>> dir(HountedBus.__init__)  # doctest: +ELLIPSIS
+['__annotations__', '__call__', ..., '__defaults__', ...]
+>>> HountedBus.__init__.__defaults__
+(['Carrie', 'Dave'],)
+>>> HountedBus.__init__.__defaults__[0] is bus2.passengers
+True
+
+"""
+
+# BEGIN HAUNTED_BUS_CLASS
+class HountedBus:
+    """A bus model hounted by ghost passengers"""
+
+    def __init__(self, passengers=[]):  # <1>
+        self.passengers = passengers  # <2>
+
+    def pick(self, name):
+        self.passengers.append(name)  # <3>
+
+    def drop(self, name):
+        self.passengers.remove(name)
+# END HAUNTED_BUS_CLASS
+