diff --git a/05_load_json_without_dupes.py b/05_load_json_without_dupes.py
new file mode 100644
index 0000000..5b767a2
--- /dev/null
+++ b/05_load_json_without_dupes.py
@@ -0,0 +1,11 @@
+import json
+
+def dict_raise_on_duplicates(ordered_pairs):
+    """reject duplicate keys"""
+    my_dict = dict()
+    for key, values in ordered_pairs:
+        if key in my_dict:
+           raise ValueError("Duplicate key: {}".format(key,))
+        else:
+           my_dict[key] = values
+    return my_dict
\ No newline at end of file
diff --git a/readme.md b/readme.md
index 94eeac3..0dae7ad 100644
--- a/readme.md
+++ b/readme.md
@@ -4,3 +4,4 @@
 1. **02_find_all_links.py**: get all links from a webpage
 1. **03_simple_twitter_manager.py**: accessing the Twitter API, example functions
 3. **04_rename_with_slice.py**: rename group of files, within a single directory, using slice
+4. **05_load_json_without_dupes.py: load json, convert to dict, raise error if there is a duplicate key