Implemented email lookup.

friend_functions.py

@@ -27,7 +27,10 @@ def get_email(people, name):
         >>> get_email(friends, "Tad Winters")
         None
     """
-    raise NotImplementedError()
+    for person in people:
+        if person["name"] == name:
+            return person["email"]
+    return None
 
 def count_favorite_colors(people, name):
     """Returns the number of colors liked by the named person. If there is no such person, returns None.