[dock] Fix key search in dictionaries

beat/core/dock.py

@@ -151,7 +151,7 @@ class Host(object):
         def _describe(image):
             '''Tries to run the "describe" app on the image, collect results'''
 
-            if Host.images_cache.has_key(image):
+            if image in Host.images_cache:
                 return Host.images_cache[image]
 
             cmd = [
@@ -275,7 +275,7 @@ class Host(object):
 
             key = description['name'] + ' (' + description['version'] + ')'
 
-            if description.has_key('databases'):
+            if 'databases' in description:
                 if (key in db_environments) and not _must_replace(image, db_environments, key):
                     continue
 
@@ -327,6 +327,7 @@ class Host(object):
             place.
 
         """
+
         cmd = [
             'docker',
             'run',
@@ -462,7 +463,7 @@ class Host(object):
         data = client.stats(container.id, decode=True, stream=False)
 
         # If CPU statistics can't be retrieved
-        if not data['cpu_stats'].has_key('system_cpu_usage'):
+        if 'system_cpu_usage' not in data['cpu_stats']:
             data['cpu_stats'] = dict(data['precpu_stats'])
 
         # If memory statistics can't be retrieved