Don't use a list comprehension as shorthand for a for loop.

gunicorn/arbiter.py

@@ -173,8 +173,8 @@ class Arbiter(object):
         are queued. Child signals only wake up the master.
         """
         # close old PIPE
-        if self.PIPE:
+        for p in self.PIPE:
-            [os.close(p) for p in self.PIPE]
+            os.close(p)
 
         # initialize the pipe
         self.PIPE = pair = os.pipe()
@@ -185,7 +185,8 @@ class Arbiter(object):
         self.log.close_on_exec()
 
         # initialize all signals
-        [signal.signal(s, self.signal) for s in self.SIGNALS]
+        for s in self.SIGNALS:
+            signal.signal(s, self.signal)
         signal.signal(signal.SIGCHLD, self.handle_chld)
 
     def signal(self, sig, frame):
@@ -454,7 +455,8 @@ class Arbiter(object):
         # do we need to change listener ?
         if old_address != self.cfg.address:
             # close all listeners
-            [l.close() for l in self.LISTENERS]
+            for l in self.LISTENERS:
+                l.close()
             # init new listeners
             self.LISTENERS = sock.create_sockets(self.cfg, self.log)
             listeners_str = ",".join([str(l) for l in self.LISTENERS])

gunicorn/workers/base.py

@@ -101,7 +101,8 @@ class Worker(object):
             util.close_on_exec(p)
 
         # Prevent fd inheritance
-        [util.close_on_exec(s) for s in self.sockets]
+        for s in self.sockets:
+            util.close_on_exec(s)
         util.close_on_exec(self.tmp.fileno())
 
         self.wait_fds = self.sockets + [self.PIPE[0]]
@@ -156,7 +157,8 @@ class Worker(object):
 
     def init_signals(self):
         # reset signaling
-        [signal.signal(s, signal.SIG_DFL) for s in self.SIGNALS]
+        for s in self.SIGNALS:
+            signal.signal(s, signal.SIG_DFL)
         # init new signaling
         signal.signal(signal.SIGQUIT, self.handle_quit)
         signal.signal(signal.SIGTERM, self.handle_exit)

gunicorn/workers/geventlet.py

@@ -134,9 +134,12 @@ class EventletWorker(AsyncWorker):
         self.notify()
         try:
             with eventlet.Timeout(self.cfg.graceful_timeout) as t:
-                [a.kill(eventlet.StopServe()) for a in acceptors]
+                for a in acceptors:
-                [a.wait() for a in acceptors]
+                    a.kill(eventlet.StopServe())
+                for a in acceptors:
+                    a.wait()
         except eventlet.Timeout as te:
             if te != t:
                 raise
-            [a.kill() for a in acceptors]
+            for a in acceptors:
+                a.kill()

gunicorn/workers/ggevent.py

@@ -143,7 +143,8 @@ class GeventWorker(AsyncWorker):
 
             # Force kill all active the handlers
             self.log.warning("Worker graceful timeout (pid:%s)" % self.pid)
-            [server.stop(timeout=1) for server in servers]
+            for server in servers:
+                server.stop(timeout=1)
         except:
             pass