Change method to static

Change allow_one_expected_tailoring_or_no_tailoring method
to private static method because it doesn't access self and
it isn't used outside of this class.

org_fedora_oscap/content_discovery.py

@@ -198,7 +198,8 @@ def _verify_fingerprint(self, fingerprint=""):
             raise content_handling.ContentCheckError(msg)
         log.info(f"Integrity check passed using {hash_obj.name} hash")
 
-    def allow_one_expected_tailoring_or_no_tailoring(self, labelled_files, expected_tailoring):
+    @staticmethod
+    def __allow_one_expected_tailoring_or_no_tailoring(labelled_files, expected_tailoring):
         tailoring_label = CONTENT_TYPES["TAILORING"]
         if expected_tailoring:
             labelled_files = ContentBringer.reduce_files(labelled_files, expected_tailoring, [tailoring_label])
@@ -214,7 +215,7 @@ def filter_discovered_content(self, labelled_files, expected_path, expected_tail
         if expected_path:
             labelled_files = ContentBringer.reduce_files(labelled_files, expected_path, categories)
 
-        labelled_files = self.allow_one_expected_tailoring_or_no_tailoring(labelled_files, expected_tailoring)
+        labelled_files = ContentBringer.__allow_one_expected_tailoring_or_no_tailoring(labelled_files, expected_tailoring)
 
         categories = (CONTENT_TYPES["CPE_DICT"], )
         if expected_cpe_path: