--- a/gamelib/missions.py	Sun May 06 21:27:33 2012 +0200
+++ b/gamelib/missions.py	Sun May 06 21:40:13 2012 +0200
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # vim:fileencoding=utf-8 ai ts=4 sts=4 et sw=4
 
-from products import DoomsdayVirus, HAND_WEAPON
+from products import HAND_WEAPON, PATHOGEN, DOOMSDAY_DEVICE
 
 MAJOR_SETBACK, FAILURE, SUCCESS, MAJOR_SUCCESS, GAME_WIN = range(5)
 
@@ -78,9 +78,9 @@
 
     def __init__(self, init_data=None):
         # Track prior approaches to this mission
-        self._prior_attempts = []
+        self._prior_attempts = set()
         if init_data:
-            self._prior_attempts = init_data
+            self._prior_attempts = set(init_data)
 
     def save_data(self):
         return self._prior_attempts
@@ -89,20 +89,26 @@
         failures = []
         reputation = 0
         for item in equipment:
-            if isinstance(item, DoomsdayVirus) and \
-                    item.NAME not in self._prior_attempts:
-                self._prior_attempts.add(item.NAME)
-                return Result(SUCCESS, 1000000, 1, "Trembling at the threat of"
-                    " your doomsday virus, the chinese government pays the"
-                    " ransom")
-            elif isinstance(item, DoomsdayVirus):
-                reputation = -1
-                failures.append("'Hah, we've developed an antidote to your"
-                        " virus, doctor'. You cannot threaten us with that"
-                        " again'")
+            if item.is_a(DOOMSDAY_DEVICE):
+                if item.NAME not in self._prior_attempts:
+                    self._prior_attempts.add(item.NAME)
+                    return Result(SUCCESS, 1000000, 1, (
+                            "Trembling at the threat of your doomsday virus,"
+                            " the chinese government pays the ransom."))
+                elif item.is_a(PATHOGEN):
+                    reputation = -1
+                    failures.append(
+                        "'Hah, we've developed an antidote to your"
+                        " pathogen, doctor. You cannot threaten us with that"
+                        " again.'")
+                else:
+                    reputation = -1
+                    failures.append(
+                        "'Hah, we know how to deal with that particular"
+                        " threat, doctor.'")
             else:
                 failures.append("You fail to inspire fear with your %s"
-                        % item.name)
+                        % item.NAME)
         return Result(FAILURE, 0, reputation, "\n".join(failures))
 
 
@@ -121,7 +127,7 @@
                     " barehanded is unsuccessful. Fortunately, everyone is"
                     " too stunned to impede your escape.")
         for item in equipment:
-            if isinstance(item, DoomsdayVirus):
+            if item.is_a(PATHOGEN):
                 if state.reputation < 10:
                     failures.append("The clerk doesn't realise the threat of"
                             " the vial you hold, and, although watching him"
@@ -132,7 +138,7 @@
                     return Result(SUCCESS, 1000, 0, "Holding up a bank with"
                             " only a small vial of clear liquid. Now that"
                             " is power.")
-            elif HAND_WEAPON in item.CATEGORIES:
+            elif item.is_a(HAND_WEAPON):
                 return Result(SUCCESS, 1000, 0, "The threat of your weapons is"
                     " enough to inspire an impressive level of cooperation")
             else:

--- a/gamelib/products.py	Sun May 06 21:27:33 2012 +0200
+++ b/gamelib/products.py	Sun May 06 21:40:13 2012 +0200
@@ -28,6 +28,9 @@
         extra = self.UPGRADE_REQUIREMENT * self.points + 1
         return lab.meet_requirements(self, extra)
 
+    def is_a(self, category):
+        return category in self.CATEGORIES
+
 
 class MachineGun(Product):
     NAME = "Machine gun"