docs: 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:]