Error in save_as_xspec used from notebook

[ferrigno]

Describe the bug
I run from a notebook
save_as_xspec.save_as_xspec(crossspec_name, direct_save=True)
I obtain

ERROR: No such device or address
Task flx2xsp 0.0 terminating with status 6

Unable to redirect prompts to the /dev/tty (at headas_stdio.c:152)
``
but if I run from the same notebook
`!flx2xsp cross_03.0_30.0_xsp.dat cross_03.0_30.0.pha cross_03.0_30.0.rsp`
It works. 

The command line version works as well.

I have no clue why

**To Reproduce**

**Expected behavior**

**Screenshots**

**Desktop (please complete the following information):**
 - OS: Ubuntu 20.04
 - e.g. 3.8.10
 - HENDRICS 7.0.2

**Additional context**
Add any other context about the problem here.