clock exercise

python/clock/clock.py

@@ -0,0 +1,26 @@
+class Clock(object):
+    def __init__(self, hour, minute):
+        self.hour, self.minute = hour, minute
+
+    def __repr__(self):
+        return '<Clock {}:{}>'.format(str(self.hour).zfill(2), str(self.minute).zfill(2))
+
+    def __eq__(self, other):
+        return self.hour == other.hour and self.minute == other.minute
+
+    def change(self, minutes):
+        self.minute += minutes
+        while self.minute >= 60 or self.minute < 0:
+            if self.minute >= 60:
+                self.hour += 1
+                self.minute -= 60
+            elif self.minute < 0:
+                self.hour -= 1
+                self.minute += 60
+        self.hour = self.hour % 24
+
+    def __add__(self, minutes):
+        return self.change(minutes)
+
+    def __sub__(self, minutes):
+        return self.change(-minutes)