Refactor code to remove alerts as per lgtm and #1176.

evennia/server/sessionhandler.py

@@ -12,10 +12,10 @@ There are two similar but separate stores of sessions:
          handle network communication but holds no game info.
 
 """
+import time
 from builtins import object
 from future.utils import listvalues
 
-from time import time
 from django.conf import settings
 from evennia.commands.cmdhandler import CMD_LOGINSTART
 from evennia.utils.logger import log_trace
@@ -89,7 +89,10 @@ def delayed_import():
     if not _ScriptDB:
         from evennia.scripts.models import ScriptDB as _ScriptDB
     # including once to avoid warnings in Python syntax checkers
-    _ServerSession, _PlayerDB, _ServerConfig, _ScriptDB
+    assert(_ServerSession)
+    assert(_PlayerDB)
+    assert(_ServerConfig)
+    assert(_ScriptDB)
 
 
 #-----------------------------------------------------------
@@ -565,7 +568,7 @@ class ServerSessionHandler(SessionHandler):
         see if any are dead or idle.
 
         """
-        tcurr = time()
+        tcurr = time.time()
         reason = _("Idle timeout exceeded, disconnecting.")
         for session in (session for session in self.values()
                         if session.logged_in and _IDLE_TIMEOUT > 0