帮我编写，Python自定义矩阵类，实现矩阵运算中的秩的运算的代码

好的，请稍等，下面是 Python 自定义矩阵类，其中包含矩阵的秩运算代码：

class Matrix:
    def __init__(self, rows, cols):
        self.rows = rows
        self.cols = cols
        self.matrix = [[0 for j in range(cols)] for i in range(rows)]

    def __str__(self):
        return '\n'.join([' '.join([str(self.matrix[i][j]) for j in range(self.cols)]) for i in range(self.rows)])

    def __getitem__(self, index):
        return self.matrix[index]

    def __setitem__(self, index, value):
        self.matrix[index] = value

    def __eq__(self, other):
        return self.matrix == other.matrix

    def rank(self):
        m = self.rows
        n = self.cols
        rank = min(m, n)
        for row in range(rank):
            if self.matrix[row][row] != 0:
                for col in range(row + 1, m):
                    c = self.matrix[col][row] / self.matrix[row][row]
                    for i in range(row, n):
                        self.matrix[col][i] -= c * self.matrix[row][i]
            else:
                reduce = True
                for i in range(row + 1, m):
                    if self.matrix[i][row] != 0:
                        self.matrix[row], self.matrix[i] = self.matrix[i], self.matrix[row]
                        reduce = False
                        break
                if reduce:
                    rank -= 1
                    for i in range(m):
                        self.matrix[i][row] = self.matrix[i][rank]
        return rank

调用方法如下：

m = Matrix(3, 3)
m[0] = [1, 2, 3]
m[1] = [4, 5, 6]
m[2] = [7, 8, 9]

print(m.rank())

输出结果为 2，即矩阵 m 的秩为 2。