on ubuntu 20.04

i am getting this

File "/home/user/.cargo/git/checkouts/rustpython-f8ef4d934ac33cd8/4c39668/vm/pylib-crate/Lib/zipimport.py", line 259, in load_module
exec(code, mod.dict)
File "/tmp/tmp_1qijfve/pip.zip/pip/_vendor/cachecontrol/filewrapper.py", line 6, in
ModuleNotFoundError: No module named 'mmap'

while running

rustpython --install-pip