Thanks dap35. You were right, point was an outdated version of pyton. When i donwload and try to force the newer version installation i realice there the problem was.
So i update Pyton following this New version 0.94.0 - How update Python in a Pi3 from 3.5.3 to 3.7.3? , later on, delete the old pyton virtual environment, , create a new one with new pyton version this way:
So i consider this close.