Python "list index out of range" error in Breadth First Traversal

I am trying to create a BFS in python. While I am proper adjacency list but Python is showing "list index out of range" error, also BFS answer is not correct all the time.

Below is the python code, I have added edges, (1, 2), (2, 3) and (3, 3)

I am trying to find BFS from vertex 2,

from collections import defaultdict

# This class represents a directed graph using adjacency
# list representation
class Graph:

    # Constructor
    def __init__(self):

        # default dictionary to store graph
        self.graph = defaultdict(list)

    # function to add an edge to graph
    def addEdge(self,u,v):
        self.graph[u].append(v)

    # Function to print a BFS of graph
    def BFS(self, s):

        # Mark all the vertices as not visited
        visited = [False]*(len(self.graph))

        # Create a queue for BFS
        queue = []

        # Mark the source node as visited and enqueue it
        queue.append(s)
        visited[s] = True

        while queue:

            # Dequeue a vertex from queue and print it
            s = queue.pop(0)
            print s,

            # Get all adjacent vertices of the dequeued
            # vertex s. If a adjacent has not been visited,
            # then mark it visited and enqueue it
            for i in self.graph[s]:

                if visited[i] == False:

                    queue.append(i)
                    visited[i] = True




# Create a graph 
g = Graph()

g.addEdge(1, 2)
g.addEdge(2, 3)
g.addEdge(3, 3)

print "Following is Breadth First Traversal (starting from vertex 2)"
g.BFS(2)

The error it is showing;

Following is Breadth First Traversal (starting from vertex 2)
2
Traceback (most recent call last):
  File "test.py", line 58, in <module>
    g.BFS(2)
  File "test.py", line 42, in BFS
    if visited[i] == False:
IndexError: list index out of range

Not sure, why it is showing out of range. I already initialised vertex[1], vertex[2] and vertex[3] as False. Also, graph[1], graph[2] and graph[3] is maintaining proper adjacency list.

Also, the BFS answer should be 2 3 but it is giving only 2