diff --git a/wani.py b/wani.py
index 916ad88..573c031 100644
--- a/wani.py
+++ b/wani.py
@@ -1026,6 +1026,27 @@ class Writer:
         return Writer(False, args.output, args.multiple_output,
                       int(args.sort_by), args.sort_reversed, args.stats)
 
+class Formatter:
+    def __init__(self, colocation_ids):
+        self.colocation_ids = colocation_ids
+        self.additional_init()
+    
+    def header_repeat(self):
+        raise NotImplementedError("Header repeat formatter not implemented")
+    def header_right(self):
+        raise NotImplementedError("Header right formatter not implemented")
+    def content_repeat(self, words, representations, idx):
+        raise NotImplementedError("Content repeat formatter not implemented")
+    def content_right(self, freq):
+        raise NotImplementedError("Content right formatter not implemented")
+    def group(self):
+        raise NotImplementedError("Group for formatter not implemented")
+    
+    def additional_init(self):
+        pass
+    def length(self):
+        return len(self.header_repeat())
+
     @staticmethod
     def make_all_writer(args):
         return Writer(True, args.all, False, -1, False, False)