Hello I am new to the Mailman community and on my try to contribute for Mailman,I started installing all packages . For Hyperkitty I followed https://hyperkitty.readthedocs.io/en/latest/development.html . Everything went fine without any errors but on accessing the hyperkitty on my browser , it shows me an error stating "A server error occurred. Please contact the administrator." and on the terminal the last 3 lines shows

File "/home/nikhil/dev/mailman/venv2/local/lib/python2.7/site-packages/django_haystack-2.5.1-py2.7.egg/haystack/backends/whoosh_backend.py", line 30, in <module> raise MissingDependency("The 'whoosh' backend requires the installation of 'Whoosh'. Please refer to the documentation.") MissingDependency: The 'whoosh' backend requires the installation of 'Whoosh'. Please refer to the documentation.

Can any one help me with figuring out the cause for this error