Style fixes and pylint hint in inventory

src/inventory.py

@@ -1,26 +1,41 @@
-from bmconfigparser import BMConfigParser
-from singleton import Singleton
+"""The Inventory singleton"""
 
 # TODO make this dynamic, and watch out for frozen, like with messagetypes
 import storage.sqlite
 import storage.filesystem
+from bmconfigparser import BMConfigParser
+from singleton import Singleton
+
 
 @Singleton
 class Inventory():
+    """
+    Inventory singleton class which uses storage backends
+    to manage the inventory.
+    """
     def __init__(self):
-        #super(self.__class__, self).__init__()
         self._moduleName = BMConfigParser().safeGet("inventory", "storage")
-        self._inventoryClass = getattr(getattr(storage, self._moduleName), "{}Inventory".format(self._moduleName.title()))
+        self._inventoryClass = getattr(
+            getattr(storage, self._moduleName),
+            "{}Inventory".format(self._moduleName.title())
+        )
         self._realInventory = self._inventoryClass()
         self.numberOfInventoryLookupsPerformed = 0
 
     # cheap inheritance copied from asyncore
     def __getattr__(self, attr):
-        try:
         if attr == "__contains__":
             self.numberOfInventoryLookupsPerformed += 1
+        try:
             realRet = getattr(self._realInventory, attr)
         except AttributeError:
-            raise AttributeError("%s instance has no attribute '%s'" %(self.__class__.__name__, attr))
+            raise AttributeError(
+                "%s instance has no attribute '%s'" %
+                (self.__class__.__name__, attr)
+            )
         else:
             return realRet
+
+    # hint for pylint: this is dictionary like object
+    def __getitem__(self, key):
+        return self._realInventory[key]