Python-сообщество

matrix =[[1,2,3,4,5],
         [5,6,7,8,9],
         [9,0,0,0,2],
         [6,5,4,3,2],
         [3,4,2,3,2]]
pattern = [[5,4,3],
           [4,2,3]]
def finder(matrix, pattern):
    width = len(matrix[0])
    height = len(matrix)
    p_width = len(pattern[0])
    p_height = len(pattern)
    def comparer(r, c):
        if c + p_width > width:
            return
        if r + p_height > height:
            return
        for i, row in enumerate(pattern):
            for j, e in enumerate(row):
                matrix_i = i + r
                matrix_j = j + c
                if matrix[matrix_i][matrix_j] != e:
                    return
        return True
    corner = pattern[0][0]
    def cmp():
        for row, sub in enumerate(matrix):
            for column, elem in enumerate(sub):
                if corner == elem:
                    if comparer(row, column):
                        return row, column
    return cmp()
print finder(matrix, pattern)