Psychopy failed to start in Ubuntu 18.04

I have followed the instructions using pip to install the PsychoPy on ubuntu 18.04LTS. However, when I run psychopy from the terminal, it informs me that “libSDL-1.2.so.0: cannot open shared object file: No such file or directory”. I have installed wxPython using “pip3 install -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-18.04/ wxPython”. Any ideas?

Thanks