adding chapter 7 source code

Chapter7/multiprocessing/process7.py

@@ -0,0 +1,18 @@
+# process7.py to show synchronization and locking
+from functools import partial
+from multiprocessing import Pool, Manager
+
+def printme (lock, msg):
+    lock.acquire()
+    try:
+        print(msg)
+    finally:
+        lock.release()
+
+with Pool(3) as proc:
+    lock = Manager().Lock()
+    func = partial(printme,lock)
+    proc.map(func, ["Orange", "Apple", "Banana",
+                             "Grapes","Pears"])
+
+print("Exiting the main process")