 b/tests/helpers.py
+import docdeid as dd
+def link_tokens(tokens: list[dd.Token]):
+    for token, next_token in zip(tokens, tokens[1:]):
+        token.set_next_token(next_token)
+        next_token.set_previous_token(token)
+    return tokens
+def linked_tokens(tokens: list[str]) -> list[dd.Token]:
+    tokens = [dd.Token(x, 0, len(x)) for x in tokens]
+    return link_tokens(tokens)