see searx.search.processors.abstract.EngineProcessor
First the method searx call the get_params method.
If the return value is not None, then the searx call the method search.
use
from searx.engines.duckduckgo import _fetch_supported_languages, supported_languages_url # NOQA
so it is possible to easily remove all unused import using autoflake:
autoflake --in-place --recursive --remove-all-unused-imports searx tests
