Removes len() on empty sequence evaluation

PEP8 suggestes, "For sequences, use the fact that empty sequences are false."

Change-Id: I4c600a7a6230a55328ee46f7c59f340f37abc18f

6 files changed, 8 insertions, 10 deletions

diff --git a/openstack/common/policy.py b/openstack/common/policy.py
index 21ea010..cd6dcfc 100644
--- a/openstack/common/policy.py
+++ b/openstack/common/policy.py
@@ -437,7 +437,7 @@ def _parse_list_rule(rule):
             or_list.append(AndCheck(and_list))
 
     # If we have only one check, omit the "or"
-    if len(or_list) == 0:
+    if not or_list:
         return FalseCheck()
     elif len(or_list) == 1:
         return or_list[0]
diff --git a/openstack/common/processutils.py b/openstack/common/processutils.py
index 09baea3..1aa1335 100644
--- a/openstack/common/processutils.py
+++ b/openstack/common/processutils.py
@@ -123,7 +123,7 @@ def execute(*cmd, **kwargs):
     elif isinstance(check_exit_code, int):
         check_exit_code = [check_exit_code]
 
-    if len(kwargs):
+    if kwargs:
         raise UnknownArgumentError(_('Got unknown keyword args '
                                      'to utils.execute: %r') % kwargs)
 
diff --git a/openstack/common/rpc/impl_zmq.py b/openstack/common/rpc/impl_zmq.py
index 7a5d814..fec299c 100644
--- a/openstack/common/rpc/impl_zmq.py
+++ b/openstack/common/rpc/impl_zmq.py
@@ -180,7 +180,7 @@ class ZmqSocket(object):
             return
 
         # We must unsubscribe, or we'll leak descriptors.
-        if len(self.subscriptions) > 0:
+        if self.subscriptions:
             for f in self.subscriptions:
                 try:
                     self.sock.setsockopt(zmq.UNSUBSCRIBE, f)
@@ -763,7 +763,7 @@ def _multi_send(method, context, topic, msg, timeout=None,
     LOG.debug(_("Sending message(s) to: %s"), queues)
 
     # Don't stack if we have no matchmaker results
-    if len(queues) == 0:
+    if not queues:
         LOG.warn(_("No matchmaker results. Not casting."))
         # While not strictly a timeout, callers know how to handle
         # this exception and a timeout isn't too big a lie.
diff --git a/openstack/common/rpc/matchmaker.py b/openstack/common/rpc/matchmaker.py
index 7366246..3d72ae7 100644
--- a/openstack/common/rpc/matchmaker.py
+++ b/openstack/common/rpc/matchmaker.py
@@ -245,7 +245,7 @@ class HeartbeatMatchMakerBase(MatchMakerBase):
         yielding for CONF.matchmaker_heartbeat_freq seconds
         between iterations.
         """
-        if len(self.hosts) == 0:
+        if not self.hosts:
             raise MatchMakerException(
                 _("Register before starting heartbeat."))
 
diff --git a/openstack/common/setup.py b/openstack/common/setup.py
index 03b0675..1b3a127 100644
--- a/openstack/common/setup.py
+++ b/openstack/common/setup.py
@@ -127,11 +127,9 @@ def _run_shell_command(cmd, throw_on_error=False):
     out = output.communicate()
     if output.returncode and throw_on_error:
         raise Exception("%s returned %d" % cmd, output.returncode)
-    if len(out) == 0:
+    if not out:
         return None
-    if len(out[0].strip()) == 0:
-        return None
-    return out[0].strip()
+    return out[0].strip() or None
 
 
 def _get_git_directory():
diff --git a/openstack/common/wsgi.py b/openstack/common/wsgi.py
index 9e92ffe..d184963 100644
--- a/openstack/common/wsgi.py
+++ b/openstack/common/wsgi.py
@@ -659,7 +659,7 @@ class RequestDeserializer(object):
         return self.headers_deserializer.deserialize(request, action)
 
     def deserialize_body(self, request, action):
-        if not len(request.body) > 0:
+        if not request.body:
             LOG.debug(_("Empty body provided in request"))
             return {}