It doesnt work, what should i do? (Linux)

##I cant activate or even see the OMEMO Plugin under Installed Plugins in Gajim

run gajim with -l gajim.plugin_system.omemo=DEBUG

###the log says: cannot import name symbol_database

do pip install --upgrade protobuf

###after pip install python-axolotl the console says:

curve25519module.c:3:20: fatal error: Python.h  file or folder  not found
compilation terminated.    
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

do: apt-get install python-dev and afterwards pip install python-axolotl again

###i still cant see the plugin

last resort pip install protobuf==2.6.1