AttributeError: module 'gnuradio.digital.qam' has no attribute 'qam_mod'

Hi everyone,

    I am still pretty new to GNU Radio, and I am trying to use the 'QAM-mod' block in GRC. However, I have encountered the following error and I am not sure how to fix this:

error message:

Traceback (most recent call last):

  File "/home/lannanjiang/gr-iio/My_Radio/QAMmodem.py", line 214, in <module>

    main()

  File "/home/lannanjiang/gr-iio/My_Radio/QAMmodem.py", line 192, in main

    tb = top_block_cls()

  File "/home/lannanjiang/gr-iio/My_Radio/QAMmodem.py", line 140, in __init__

    self.digital_qam_mod_2 = digital.qam.qam_mod(

AttributeError: module 'gnuradio.digital.qam' has no attribute 'qam_mod'

 The following is what I typed to install gnuradio and gr-iio on a 64bit guest machine, Ubuntu 20.04 LTS. 

  

  sudo apt install gnuradio

  sudo apt install swig

  sudo apt install liborc-dev

  git clone -b upgrade-3.8 https://github.com/analogdevicesinc/gr-iio.git

  cd gr-iio

  cmake .

  make

  sudo make install

  cd ..

  sudo ldconfig

I have looked up similar questions asked by others but I was unable to resolve this error.

   By the way, I was able tp use FM mod and demod blocks GNU radio, but I keep getting the "no attribute error" for QAM mod and constellation modulator blocks.

 Please help me with this, any suggestions will be appreciated!

Thanks in advance

Lannan Jiang