Problem between asdf and sunpy

[Yannick Roehlly <yannick.roehlly@gmail.com>]

Hi,

On my system, trying to save an astropy table to asdf raises this :

DistributionNotFound: The 'parfive[ftp]>=1.1.0' distribution was not found and 
is required by the application

This happens when asdf parses the asdf_extensions entry points and try to 
execute them.  This can be manually done with:

for ep in iter_entry_points(group="asdf_extensions"):
    print(ep)
    ext = ep.load()

Installing python3-parfive does not solve the problem because the package does 
not contain the ftp module and the error becomes:

UnknownExtra: parfive 1.1.1 has no such extra feature 'ftp'

Do you think I should report the bug against asdf or sunpy?

Regards,

Yannick