From 17645c77e5294e4be82516d9fc54d177661bcb0c Mon Sep 17 00:00:00 2001
From: Kaivalya Rawal <kaivalyaraw@gmail.com>
Date: Wed, 22 Mar 2017 15:47:35 +0530
Subject: [PATCH 1/4] replace assert with if test in add_thing

---
 agents.py | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/agents.py b/agents.py
index 047eb3fd6..e1b987b14 100644
--- a/agents.py
+++ b/agents.py
@@ -297,12 +297,14 @@ def add_thing(self, thing, location=None):
         for it. (Shouldn't need to override this."""
         if not isinstance(thing, Thing):
             thing = Agent(thing)
-        assert thing not in self.things, "Don't add the same thing twice"
-        thing.location = location if location is not None else self.default_location(thing)
-        self.things.append(thing)
-        if isinstance(thing, Agent):
-            thing.performance = 0
-            self.agents.append(thing)
+        if thing in self.things:
+            print("Can't add the same thing twice")
+        else:
+            thing.location = location if location is not None else self.default_location(thing)
+            self.things.append(thing)
+            if isinstance(thing, Agent):
+                thing.performance = 0
+                self.agents.append(thing)
 
     def delete_thing(self, thing):
         """Remove a thing from the environment."""

From 98e0a40cfc80f031efec0241a56b0f31e3fd82e7 Mon Sep 17 00:00:00 2001
From: Kaivalya Rawal <kaivalyaraw@gmail.com>
Date: Wed, 22 Mar 2017 15:49:05 +0530
Subject: [PATCH 2/4] removed inline assert

---
 agents.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/agents.py b/agents.py
index e1b987b14..da10f2760 100644
--- a/agents.py
+++ b/agents.py
@@ -85,10 +85,9 @@ def __init__(self, program=None):
         self.bump = False
         self.holding = []
         self.performance = 0
-        if program is None:
+        if program is None or not isinstance(program, collections.Callable):
             def program(percept):
                 return eval(input('Percept={}; action? '.format(percept)))
-        assert isinstance(program, collections.Callable)
         self.program = program
 
     def can_grab(self, thing):

From 732f48bb622e57445042c436e1922d52b48be467 Mon Sep 17 00:00:00 2001
From: Kaivalya Rawal <kaivalyaraw@gmail.com>
Date: Wed, 22 Mar 2017 15:56:33 +0530
Subject: [PATCH 3/4] added unit test to check edit

---
 tests/test_agents.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/test_agents.py b/tests/test_agents.py
index 0162a78b8..699e317f7 100644
--- a/tests/test_agents.py
+++ b/tests/test_agents.py
@@ -1,4 +1,5 @@
 from agents import Direction
+from agents import Agent
 from agents import ReflexVacuumAgent, ModelBasedVacuumAgent, TrivialVacuumEnvironment
 
 
@@ -65,3 +66,9 @@ def test_ModelBasedVacuumAgent() :
     # check final status of the environment
     assert environment.status == {(1,0):'Clean' , (0,0) : 'Clean'}
 
+def test_Agent():
+    def constant_prog(percept):
+        return percept
+    agent = Agent(constant_prog)
+    result = agent.program(5)
+    assert result == 5

From 84144b3b515cb1177a60e50d9a89771a6a60d5b8 Mon Sep 17 00:00:00 2001
From: Kaivalya Rawal <kaivalyaraw@gmail.com>
Date: Wed, 22 Mar 2017 22:21:54 +0530
Subject: [PATCH 4/4] improve user interface

---
 agents.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/agents.py b/agents.py
index da10f2760..ff049aa4a 100644
--- a/agents.py
+++ b/agents.py
@@ -86,6 +86,7 @@ def __init__(self, program=None):
         self.holding = []
         self.performance = 0
         if program is None or not isinstance(program, collections.Callable):
+            print("Can't find a valid program for {}, falling back to default.".format(self.__class__.__name__))
             def program(percept):
                 return eval(input('Percept={}; action? '.format(percept)))
         self.program = program