Refactoring of submit module, some fixes

tests/test_data.py

@@ -1,15 +1,16 @@
 """Maigret data test functions"""
 
 from maigret.utils import is_country_tag
-from maigret.sites import SUPPORTED_TAGS
 
 
 def test_tags_validity(default_db):
     unknown_tags = set()
 
+    tags = default_db._tags
+
     for site in default_db.sites:
         for tag in filter(lambda x: not is_country_tag(x), site.tags):
-            if tag not in SUPPORTED_TAGS:
+            if tag not in tags:
                 unknown_tags.add(tag)
 
     assert unknown_tags == set()