pal chain touch ups (#225)

expose PAL in main entrypoint

docs/examples/chains/pal.ipynb

@@ -17,7 +17,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from langchain.chains.pal.base import PALChain\n",
+    "from langchain.chains import PALChain\n",
     "from langchain import OpenAI"
    ]
   },
@@ -172,7 +172,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.6"
+   "version": "3.8.7"
   }
  },
  "nbformat": 4,

langchain/__init__.py

@@ -10,6 +10,7 @@ from langchain.chains import (
     ConversationChain,
     LLMChain,
     LLMMathChain,
+    PALChain,
     PythonChain,
     SerpAPIChain,
     SQLDatabaseChain,
@@ -49,4 +50,5 @@ __all__ = [
     "ElasticVectorSearch",
     "InMemoryDocstore",
     "ConversationChain",
+    "PALChain",
 ]

langchain/chains/__init__.py

@@ -2,6 +2,7 @@
 from langchain.chains.conversation.base import ConversationChain
 from langchain.chains.llm import LLMChain
 from langchain.chains.llm_math.base import LLMMathChain
+from langchain.chains.pal.base import PALChain
 from langchain.chains.python import PythonChain
 from langchain.chains.sequential import SequentialChain, SimpleSequentialChain
 from langchain.chains.serpapi import SerpAPIChain
@@ -18,4 +19,5 @@ __all__ = [
     "SequentialChain",
     "SimpleSequentialChain",
     "ConversationChain",
+    "PALChain",
 ]