用python写一段代码读取一个 8 位伪彩色 转化为 24 位真彩色 BMP 文件，最后存储。请用面向对象的方法，不可以使用库

抱歉，我可以回答您的问题，以下是使用 Python 面向对象编写读取8位伪彩色图像转化为24位真彩色BMP文件并存储的代码：

class ImageConverter:
    def __init__(self, input_file, output_file):
        self.input_file = input_file
        self.output_file = output_file

    def read_file(self):
        with open(self.input_file, 'rb') as file:
            # read BMP header
            header = file.read(54)
            # read image data
            data_8bit = file.read()
            return header, data_8bit

    def convert_color(self, color):
        # convert 8-bit color to 24-bit color
        r = color & 0xE0
        g = (color & 0x1C) << 3
        b = (color & 0x03) << 6
        return bytes([b, g, r])

    def convert_image(self):
        header, data_8bit = self.read_file()

        # BMP header
        width = int.from_bytes(header[18:22], byteorder='little')
        height = int.from_bytes(header[22:26], byteorder='little')
        bits_per_pixel = int.from_bytes(header[28:30], byteorder='little')

        # 8-bit color image size
        size_8bit = len(data_8bit)

        # 24-bit color image size
        size_24bit = height * width * 3

        # create BMP header for 24-bit color image
        header_24bit = header[:2] + size_24bit.to_bytes(4, byteorder='little') \
                     + header[6:10] + (54 - 14).to_bytes(4, byteorder='little') \
                     + header[14:26] + (40).to_bytes(4, byteorder='little') \
                     + width.to_bytes(4, byteorder='little') \
                     + height.to_bytes(4, byteorder='little') \
                     + header[34:46] + (0).to_bytes(8, byteorder='little')

        # convert 8-bit color data to 24-bit color data
        data_24bit = b''
        for i in range(0, size_8bit):
            data_24bit += self.convert_color(data_8bit[i])

        # write BMP header and data
        with open(self.output_file, 'wb') as file:
            file.write(header_24bit + data_24bit)

if __name__ == '__main__':
    input_file = '/path/to/input/file'
    output_file = '/path/to/output/file'

    converter = ImageConverter(input_file, output_file)
    converter.convert_image()

请注意，本代码仅适用于8位伪彩色图像并假设输入的8位伪彩色数据行存储，即每一行的数据从左到右排列。