Rename method get_channels to _get_channels in tdm_loader

The public `get_channels` function is renamed to the private method `_get_channels` in 'tdm_loader.py'. This is due to internal use only, to provide more clarity and prevent unintended external access.

Author: espenenesNOV

tdm_loader/tdm_loader.py

@@ -170,7 +170,7 @@ def _get_usi_from_txt(txt):
         return re.findall(r'id\("(.+?)"\)', txt)
 
     @cache
-    def get_channels(self, group_id):
+    def _get_channels(self, group_id):
         group = self._xml_chgs[group_id]
         return {v: i for i, v in enumerate(re.findall(r'id\("(.+?)"\)', group.find("channels").text))}