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

[lannan jiang]

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