complete the code in python

# ENUMS

UP = 0

LEFT = 1

DOWN = 2

RIGHT = 3

def BFS(puzzle):

"""

Breadth-First Search.

Arguments:

- puzzle: Node object representing initial state of the puzzle

Return:

final_solution: An ordered list of moves representing the final solution.

"""

final_solution = []

# TODO: WRITE CODE

return final_solution

# test the code using the main.py

from search import BFS, DFS, A_Star_H1, A_Star_H2, UP, DOWN, LEFT, RIGHT

def get_move_string(moves):

"""

Helper function to print moves.

"""

move_string = ""

if len(moves) == 0:

return "NONE"

for move in moves:

if move == UP:

move_string = move_string + "U "

elif move == LEFT:

move_string = move_string + "L "

elif move == DOWN:

move_string = move_string + "D "

elif move == RIGHT:

move_string = move_string + "R "

else:

move_string = move_string + "INVALID "

return move_string

def read_puzzle(filename):

"""

Helper to read a puzzle from a file.

Arguments:

filename: Name of file to read from.

"""

puzzle = []

with open(filename, "r") as f:

for line in f.readlines():

puzzle.append(line.split(' '))

return puzzle

def run_test(size, filename):

"""

Takes a filename,

then creates a puzzle,

reads it in from file,

and runs each of the search algorithms

"""

print(f"{filename}:")

puzzle = read_puzzle(filename)

moves = BFS(puzzle)

print(" BFS | " + get_move_string(moves))

puzzle = read_puzzle(filename)

moves = DFS(puzzle)

print(" DFS | " + get_move_string(moves))

puzzle = read_puzzle(filename)

moves = A_Star_H1(puzzle)

print(" A* H1 | " + get_move_string(moves))

puzzle = read_puzzle(filename)

moves = A_Star_H2(puzzle)

print(" A* H2 | " + get_move_string(moves))

print("-" * 20)

run_test(3, 'test_data/ex1.txt')

run_test(3, 'test_data/ex2.txt')

run_test(3, 'test_data/ex3.txt')