together[minor]: Update endpoint to non deprecated version (#19649)

- **Updating Together.ai Endpoint**: "langchain_together: Updated
Deprecated endpoint for partner package"

- Description: The inference API of together is deprecates, do replaced
with completions and made corresponding changes.
- Twitter handle: @dev_yashmathur

---------

Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/partners/together/langchain_together/llms.py

@@ -1,5 +1,6 @@
 """Wrapper around Together AI's Completion API."""
 import logging
+import warnings
 from typing import Any, Dict, List, Optional
 
 import requests
@@ -34,13 +35,14 @@ class Together(LLM):
             model = Together(model_name="mistralai/Mixtral-8x7B-Instruct-v0.1")
     """
 
-    base_url: str = "https://api.together.xyz/inference"
-    """Base inference API URL."""
+    base_url: str = "https://api.together.xyz/v1/completions"
+    """Base completions API URL."""
     together_api_key: SecretStr
     """Together AI API key. Get it here: https://api.together.xyz/settings/api-keys"""
     model: str
     """Model name. Available models listed here: 
-        https://docs.together.ai/docs/inference-models
+        Base Models: https://docs.together.ai/docs/inference-models#language-models
+        Chat Models: https://docs.together.ai/docs/inference-models#chat-models
     """
     temperature: Optional[float] = None
     """Model temperature."""
@@ -82,13 +84,28 @@ class Together(LLM):
         )
         return values
 
+    @root_validator()
+    def validate_max_tokens(cls, values: Dict) -> Dict:
+        """
+        The v1 completions endpoint, has max_tokens as required parameter.
+        Set a default value and warn if the parameter is missing.
+        """
+        if values.get("max_tokens") is None:
+            warnings.warn(
+                "The completions endpoint, has 'max_tokens' as required argument. "
+                "The default value is being set to 200 "
+                "Consider setting this value, when initializing LLM"
+            )
+            values["max_tokens"] = 200  # Default Value
+        return values
+
     @property
     def _llm_type(self) -> str:
         """Return type of model."""
         return "together"
 
     def _format_output(self, output: dict) -> str:
-        return output["output"]["choices"][0]["text"]
+        return output["choices"][0]["text"]
 
     @staticmethod
     def get_user_agent() -> str:
@@ -148,9 +165,6 @@ class Together(LLM):
             )
 
         data = response.json()
-        if data.get("status") != "finished":
-            err_msg = data.get("error", "Undefined Error")
-            raise Exception(err_msg)
 
         output = self._format_output(data)
 
@@ -203,9 +217,5 @@ class Together(LLM):
 
                 response_json = await response.json()
 
-                if response_json.get("status") != "finished":
-                    err_msg = response_json.get("error", "Undefined Error")
-                    raise Exception(err_msg)
-
                 output = self._format_output(response_json)
                 return output