Implement the breadth-first search (BFS) algorithm in the breadthFirstSearch function in search.py. Again, write a graph search algorithm that avoids expanding any already visited states.

def breadthFirstSearch(problem: SearchProblem):

"""Search the shallowest nodes in the search tree first."""

"*** YOUR CODE HERE ***"

util.raiseNotDefined()

Please answer the above question in bold in PYTHON CODE, thank you!