Added solution code

Solutions/7_10/timethis.py

@@ -0,0 +1,21 @@
+# timethis.py
+
+import time
+
+def timethis(func):
+    def wrapper(*args, **kwargs):
+        start = time.time()
+        try:
+            return func(*args,**kwargs)
+        finally:
+            end = time.time()
+            print("%s.%s : %f" % (func.__module__,func.__name__,end-start))
+    return wrapper
+
+if __name__ == '__main__':
+    @timethis
+    def countdown(n):
+        while n > 0:
+            n-= 1
+
+    countdown(1000000)