update sdk document (#2374)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

sdk/python/ragflow/ragflow.py

@@ -19,7 +19,7 @@ import requests
 
 from .modules.assistant import Assistant
 from .modules.dataset import DataSet
-
+from .modules.document import Document
 
 class RAGFlow:
     def __init__(self, user_key, base_url, version='v1'):
@@ -142,3 +142,32 @@ class RAGFlow:
                 result_list.append(Assistant(self, data))
             return result_list
         raise Exception(res["retmsg"])
+
+    def create_document(self, ds:DataSet, name: str, blob: bytes) -> bool:
+        url = f"/doc/dataset/{ds.id}/documents/upload"
+        files = {
+            'file': (name, blob)
+        }
+        data = {
+            'kb_id': ds.id
+        }
+        headers = {
+            'Authorization': f"Bearer {ds.rag.user_key}"
+        }
+
+        response = requests.post(self.api_url + url, data=data, files=files,
+                                 headers=headers)
+
+        if response.status_code == 200 and response.json().get('retmsg') == 'success':
+            return True
+        else:
+            raise Exception(f"Upload failed: {response.json().get('retmsg')}")
+
+        return False
+    def get_document(self, id: str = None, name: str = None) -> Document:
+        res = self.get("/doc/infos", {"id": id, "name": name})
+        res = res.json()
+        if res.get("retmsg") == "success":
+            return Document(self, res['data'])
+        raise Exception(res["retmsg"])
+