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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 single_read(self, register):
        '''
        Reads data from desired register only once. 
        '''
        
        comm_reg = (0b00010 << 3) + register

        if register == self.AD7730_STATUS_REG:
            bytes_num = 1
        elif register == self.AD7730_DATA_REG:
            bytes_num = 3
        elif register == self.AD7730_MODE_REG:
            bytes_num = 2
        elif register == self.AD7730_FILTER_REG:
            bytes_num = 3
        elif register == self.AD7730_DAC_REG:
            bytes_num = 1
        elif register == self.AD7730_OFFSET_REG:
            bytes_num = 3
        elif register == self.AD7730_GAIN_REG:
            bytes_num = 3
        elif register == self.AD7730_TEST_REG:
            bytes_num = 3

        command = [comm_reg] + ([0x00] * bytes_num)
        spi.SPI_write(self.CS, command)
        data = spi.SPI_read(bytes_num + 1)        
        return data[1:]