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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build(matrix):
 """Yield lines generated from given matrix"""

    max_x = max(matrix, key=lambda t: t[0])[0]
    min_x = min(matrix, key=lambda t: t[0])[0]
    max_y = max(matrix, key=lambda t: t[1])[1]
    min_y = min(matrix, key=lambda t: t[1])[1]
    yield from (
        # '{}:'.format(j).ljust(4) + ''.join(matrix[i, j] for i in range(min_x, max_x+1))
        ''.join(matrix[i, j] for i in range(min_x, max_x+1))
        for j in range(min_y, max_y+1)
    )