Update README.md

README.md

@@ -20,6 +20,14 @@ size_categories:
 This is an easy-to-use huggingface dataset to access the [lichess game database](https://database.lichess.org/). For now it supports only the standard games 
 but other variant will be added shortly.
 
+Requirements:
+
+```
+chess
+zstandard
+```
+
+
 ### Supported Tasks and Leaderboards
 
 It is intended for pretraining text generation models for chess games (in a PGN format).
@@ -39,8 +47,9 @@ dataset = load_dataset("lichess_games", "2013-06", streaming=True)
 
 Examples (3 rows from june 2013):
 
+<details>
+  
 ```
-
 {'text': '[Event "Rated Bullet game"]\n'
          '[Site "https://lichess.org/in28emmw"]\n'
          '[Date "????.??.??"]\n'
@@ -116,6 +125,9 @@ Examples (3 rows from june 2013):
          '30. Rg1 0-1'}
 ```
 
+</details>
+
+
 ### Data Fields
 
 Only a single column "text". Each row contains a single game in PGN format.
@@ -146,6 +158,7 @@ No splits only the file per dates.
 ### Source Data
 
 The underlying data are provided and maintained by the Lichess team and provided under CC0 license (https://database.lichess.org/). I only provide the huggingface interface here.
+The loading script download the zstd files and reads from them on the fly without decompressing the whole file, and parses the games using python-chess.
 
 #### Initial Data Collection and Normalization