Add process used buybox (#150)

* add process buy box

* add in buy box info

* fix typing

README.rst

@@ -249,6 +249,34 @@ If you plan to do a lot of simulatneous query, you might want to speedup query u
     products = await api.query('059035342X', wait=False)
 
 
+Buy Box Statistics
+~~~~~~~~~~~~~~~~~~
+To load used buy box statistics, you have to enable ``offers``. This example
+loads in product offers and converts the buy box data into a
+``pandas.DataFrame``.
+
+.. code:: pycon
+
+    >>> import keepa
+    >>> key = '<REAL_KEEPA_KEY>'
+    >>> api = keepa.Keepa(key)
+    >>> response = api.query('B0088PUEPK', offers=20)
+    >>> product = response[0]
+    >>> buybox_info = product['buyBoxUsedHistory']
+    >>> df = keepa.process_used_buybox(buybox_info)
+                   datetime         user_id         condition  isFBA
+    0   2022-11-02 16:46:00  A1QUAC68EAM09F   Used - Like New   True
+    1   2022-11-13 10:36:00  A18WXU4I7YR6UA  Used - Very Good  False
+    2   2022-11-15 23:50:00   AYUGEV9WZ4X5O   Used - Like New  False
+    3   2022-11-17 06:16:00  A18WXU4I7YR6UA  Used - Very Good  False
+    4   2022-11-17 10:56:00   AYUGEV9WZ4X5O   Used - Like New  False
+    ..                  ...             ...               ...    ...
+    115 2023-10-23 10:00:00   AYUGEV9WZ4X5O   Used - Like New  False
+    116 2023-10-25 21:14:00  A1U9HDFCZO1A84   Used - Like New  False
+    117 2023-10-26 04:08:00   AYUGEV9WZ4X5O   Used - Like New  False
+    118 2023-10-27 08:14:00  A1U9HDFCZO1A84   Used - Like New  False
+    119 2023-10-27 12:34:00   AYUGEV9WZ4X5O   Used - Like New  False
+
 Contributing
 ------------
 Contribute to this repository by forking this repository and installing in

src/keepa/__init__.py

@@ -7,6 +7,7 @@
     convert_offer_history,
     format_items,
     keepa_minutes_to_time,
+    process_used_buybox,
     run_and_get,
 )
 from keepa.plotting import plot_product  # noqa: F401