Add missing import functools in chapter 7

Author: yukinarit

src/7/making_an_n-argument_callable_work_as_a_callable_with_fewer_arguments/example1.py

@@ -1,5 +1,7 @@
 # Example of using partial() with sorting a list of (x,y) coordinates
 
+import functools
+
 points = [ (1, 2), (3, 4), (5, 6), (7, 7) ]
 
 import math
@@ -9,5 +11,5 @@ def distance(p1, p2):
     return math.hypot(x2 - x1, y2 - y1)
 
 pt = (4,3)
-points.sort(key=partial(distance, pt))
+points.sort(key=functools.partial(distance, pt))
 print(points)

src/7/making_an_n-argument_callable_work_as_a_callable_with_fewer_arguments/example2.py

@@ -1,5 +1,7 @@
 # Using partial to supply extra arguments to a callback function
 
+import functools
+
 def output_result(result, log=None):
     if log is not None:
         log.debug('Got: %r', result)
@@ -17,6 +19,6 @@ def add(x, y):
     log = logging.getLogger('test')
 
     p = Pool()
-    p.apply_async(add, (3, 4), callback=partial(output_result, log=log))
+    p.apply_async(add, (3, 4), callback=functools.partial(output_result, log=log))
     p.close()
     p.join()