community[patch]: standardize chat init args (#20844)

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community:perplexity[patch]: standardize init args

updated pplx_api_key and request_timeout so that aliased to api_key, and
timeout respectively. Added test that both continue to set the same
underlying attributes.

Related to
[20085](https://github.com/langchain-ai/langchain/issues/20085)

---------

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

libs/community/langchain_community/chat_models/perplexity.py

@@ -1,4 +1,5 @@
 """Wrapper around Perplexity APIs."""
+
 from __future__ import annotations
 
 import logging
@@ -63,10 +64,12 @@ class ChatPerplexity(BaseChatModel):
     """What sampling temperature to use."""
     model_kwargs: Dict[str, Any] = Field(default_factory=dict)
     """Holds any model parameters valid for `create` call not explicitly specified."""
-    pplx_api_key: Optional[str] = None
+    pplx_api_key: Optional[str] = Field(None, alias="api_key")
     """Base URL path for API requests, 
     leave blank if not using a proxy or service emulator."""
-    request_timeout: Optional[Union[float, Tuple[float, float]]] = None
+    request_timeout: Optional[Union[float, Tuple[float, float]]] = Field(
+        None, alias="timeout"
+    )
     """Timeout for requests to PerplexityChat completion API. Default is 600 seconds."""
     max_retries: int = 6
     """Maximum number of retries to make when generating."""

libs/community/tests/unit_tests/chat_models/test_perplexity.py

@@ -1,4 +1,5 @@
 """Test Perplexity Chat API wrapper."""
+
 import os
 
 import pytest
@@ -25,6 +26,17 @@ def test_perplexity_initialization() -> None:
     """Test perplexity initialization."""
     # Verify that chat perplexity can be initialized using a secret key provided
     # as a parameter rather than an environment variable.
-    ChatPerplexity(
-        model="test", perplexity_api_key="test", temperature=0.7, verbose=True
-    )
+    for model in [
+        ChatPerplexity(
+            model="test", timeout=1, api_key="test", temperature=0.7, verbose=True
+        ),
+        ChatPerplexity(
+            model="test",
+            request_timeout=1,
+            pplx_api_key="test",
+            temperature=0.7,
+            verbose=True,
+        ),
+    ]:
+        assert model.request_timeout == 1
+        assert model.pplx_api_key == "test"