diff --git a/prompts.py b/prompts.py
index 2ed18ba6b..381eb1dc1 100644
--- a/prompts.py
+++ b/prompts.py
@@ -57,6 +57,7 @@ THE ORIGINAL BLOCK MUST BE THE *EXACT* LINES FROM THE FILE. IT *MUST* INCLUDE:
   - ALL THE ORIGINAL LEADING SPACES AND INDENTATION!
 
 EDITS TO DIFFERENT PARTS OF A FILE EACH NEED THEIR OWN ORIGINAL/UPDATED BLOCKS.
+EVEN NEARBY PARTS NEED THEIR OWN ORIGINAL/UPDATED BLOCKS.
 '''
 
 
diff --git a/utils.py b/utils.py
new file mode 100644
index 000000000..7a1831c7c
--- /dev/null
+++ b/utils.py
@@ -0,0 +1,43 @@
+import math
+
+from difflib import SequenceMatcher
+
+# from dump import dump
+
+
+def replace_most_similar_chunk(whole, part, replace):
+    similarity_thresh = 0.8
+    max_similarity = 0
+    most_similar_chunk_start = -1
+    most_similar_chunk_end = -1
+
+    whole_lines = whole.splitlines()
+    part_lines = part.splitlines()
+
+    scale = 0.1
+    min_len = math.floor(len(part_lines) * (1 - scale))
+    max_len = math.ceil(len(part_lines) * (1 + scale))
+
+    for length in range(min_len, max_len):
+        for i in range(len(whole_lines) - length + 1):
+            chunk = whole_lines[i : i + length + 1]
+            chunk = "\n".join(chunk)
+
+            similarity = SequenceMatcher(None, chunk, part).ratio()
+
+            if similarity > max_similarity and similarity:
+                max_similarity = similarity
+                most_similar_chunk_start = i
+                most_similar_chunk_end = i + length + 1
+
+    if max_similarity < similarity_thresh:
+        return
+
+    replace_lines = replace.splitlines()
+    modified_whole = (
+        whole_lines[:most_similar_chunk_start]
+        + replace_lines
+        + whole_lines[most_similar_chunk_end:]
+    )
+    modified_whole = "\n".join(modified_whole)
+    return modified_whole