docs: update README with client batch check info

Author: jimmyjames

README.md

@@ -719,8 +719,9 @@ response = await fga_client.check(body, options)
 
 ##### Batch Check
 
-Run a set of [checks](#check). Batch Check will return `allowed: false` if it encounters an error, and will return the error in the body.
-If 429s or 5xxs are encountered, the underlying check will retry up to 3 times before giving up.
+Similar to [check](#check), but instead of checking a single user-object relationship, accepts a list of relationships to check. Requires OpenFGA version 1.8.0 or greater.
+
+[API Documentation](https://openfga.dev/api/service#/Relationship%20Queries/BatchCheck)
 
 ```python
 # from openfga_sdk import OpenFgaClient
@@ -824,6 +825,82 @@ response = await fga_client.batch_check(ClientBatchCheckRequest(checks=checks),
 # ]
 ```
 
+If you are using an OpenFGA version less than 1.8.0, you can use the `clientBatchCheck` function, 
+which calls `check` in parallel. It will return `allowed: false` if it encounters an error, and will return the error in the body.
+If 429s or 5xxs are encountered, the underlying check will retry up to 3 times before giving up.
+
+```python
+# from openfga_sdk import OpenFgaClient
+# from openfga_sdk.client import ClientCheckRequest
+# from openfga_sdk.client.models import ClientTuple
+# Initialize the fga_client
+# fga_client = OpenFgaClient(configuration)
+
+options = {
+    # You can rely on the model id set in the configuration or override it for this specific request
+    "authorization_model_id": "01GXSA8YR785C4FYS3C0RTG7B1"
+}
+body = [ClientCheckRequest(
+    user="user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+    relation="viewer",
+    object="document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+@@ -748,7 +750,7 @@
+    context=dict(
+        ViewCount=100
+    )
+), ClientCheckRequest(
+    user="user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+    relation="admin",
+    object="document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+@@ -759,20 +761,21 @@
+            object="document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+        ),
+    ]
+), ClientCheckRequest(
+    user="user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+    relation="creator",
+    object="document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+), ClientCheckRequest(
+    user="user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+    relation="deleter",
+    object="document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+)]
+
+response = await fga_client.batch_check(body, options)
+# response.responses = [{
+#   allowed: false,
+#   request: {
+#     user: "user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+#     relation: "viewer",
+#     object: "document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+@@ -787,7 +790,8 @@
+#   }
+# }, {
+#   allowed: false,
+#   request: {
+#     user: "user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+#     relation: "admin",
+#     object: "document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+@@ -799,35 +803,40 @@
+#   }
+# }, {
+#   allowed: false,
+#   request: {
+#     user: "user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+#     relation: "creator",
+#     object: "document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+#   },
+#   error: <FgaError ...>
+# }, {
+#   allowed: true,
+#   request: {
+#     user: "user:81684243-9356-4421-8fbf-a4f8d36aa31b",
+#     relation: "deleter",
+#     object: "document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a",
+#   }},
+# ]
+```
+
 #### Expand
 
 Expands the relationships in userset tree format.