diff --git a/pull_requests.py b/pull_requests.py
index 8209b67..93e7d7a 100644
--- a/pull_requests.py
+++ b/pull_requests.py
@@ -79,20 +79,7 @@ def reset_repo_to_latest_commit(repo_path: str) -> None:
     run_git_cmd(["reset", "--hard", current_branch], repo_path)
 
 
-def get_diffs_before(repo: Repository, pr: PullRequest) -> dict[str, str]:
-    comments = list(pr.get_review_comments())
-    comments.sort(key=lambda comment: comment.created_at)
-    first_comment = comments[0]
-    try:
-        return {
-            file.filename: file.patch
-            for file in repo.compare(pr.base.sha, first_comment.commit_id).files
-        }
-    except GithubException as e:
-        raise NoDiffsBeforeError(e)
-
-
-def get_diffs_after(repo: Repository, pr: PullRequest) -> dict[str, str]:
+def get_last_commit_before_comments(pr: PullRequest) -> Commit:
     comments = list(pr.get_review_comments())
     commits = list(pr.get_commits())
     comments.sort(key=lambda comment: comment.created_at)
@@ -103,7 +90,22 @@ def get_diffs_after(repo: Repository, pr: PullRequest) -> dict[str, str]:
     for commit in commits[:]:
         if commit.commit.author.date > first_comment.created_at:
             commits.remove(commit)
-    last_commit_before_comments = commits[-1]
+    return commits[-1]
+
+
+def get_diffs_before(repo: Repository, pr: PullRequest) -> dict[str, str]:
+    last_commit_before_comments = get_last_commit_before_comments(pr)
+    try:
+        return {
+            file.filename: file.patch
+            for file in repo.compare(pr.base.sha, last_commit_before_comments.sha).files
+        }
+    except GithubException as e:
+        raise NoDiffsBeforeError(e)
+
+
+def get_diffs_after(repo: Repository, pr: PullRequest) -> dict[str, str]:
+    last_commit_before_comments = get_last_commit_before_comments(pr)
     try:
         return {
             file.filename: file.patch