First draft of Python V2 migration guide (#657)

* remove references to dataclass objects

* Fix a copy-paste error.

* remove extra file

* Fix a copy-paste error.

* Fix a copy-paste error.

* remove extra file

* Fix a copy-paste error.

* add new parameter to node and dataframe

* formatting fixes

* remove unused file

* Fix broken link

* Add links to browser page for constraint properties

* Remove unused file

* Start work on Python library migration doc

* More work on migration guide

* More work on examples

* More work on examples

* More work on examples

* Various formatting, wording improvements

* More examples and pandas examples

* Some fixes

* restructuring

* fix numbering

* Add notes about future deprecation

* Slight edit

* Remove v1 reference from overview

* Remove v1 reference from overview

* Address Natalie's comments

Author: kmoscoe

api/index.md

@@ -28,7 +28,7 @@ The endpoints can be roughly grouped into four categories:
 
 -   **Graph query/SPARQL**: Given a subgraph where some of the nodes are
     variables, retrieve possible matches. This corresponds to a subset of the
-    graph query language [SPARQL](https://www.w3.org/TR/rdf-sparql-query/){: target="_blank"}. This is useful for complex node connections which would require multiple API calls; for example, "hate crimes motivated by disability status in Californian cities".
+    graph query language [SPARQL](https://www.w3.org/TR/rdf-sparql-query/){: target="_blank"}. This is useful for complex node connections which would require multiple API calls; for example, "hate crimes motivated by disability status in Californian cities". 
 
 In addition, Data Commons provides additional tools for accessing its data that call the REST APIs under the hood:
 
@@ -47,7 +47,6 @@ A key is required by some APIs to authenticate and authorize requests.
 - Data Commons NL API requests (used by the [DataGemma](https://ai.google.devgit/gemma/docs/datagemma){: target="_blank"} tool). These are served by endpoints at `nl.datacommons.org`.
 
 A key is currently not required for the following, although this may change in the future:
-- V1 Python and Pandas client libraries
 - Google Sheets
 - Web Components
 
@@ -57,7 +56,6 @@ Data Commons API keys are managed by a self-service portal. To obtain an API key
 
 To use the key in requests, see the relevant documentation:
 - [REST V2 APIs](/api/rest/v2/index.html#authentication).
-- [REST V1 APIs](/api/rest/v1/getting_started.html#authentication).
 - [Python/Pandas V2 APIs](api/python/v2/index.html#authentication).
 - For NL APIs in DataGemma, see the Colab notebooks in [https://github.com/datacommonsorg/llm-tools/tree/main/notebooks](https://github.com/datacommonsorg/llm-tools/tree/main/notebooks){: target="_blank"}
 

api/pandas/index.md

@@ -8,15 +8,15 @@ has_children: true
 
 # Data Commons Pandas API
 
+> **Note:** This version of the Data Commons Python API will be deprecated in early 2026. Please migrate your applications to [V2](/api/python/v2). For help on translating your requests, see the [Migration guide](/api/python/v2/migration.html).
+
 The **Data Commons Pandas API** is a superset of the Data Commons Python API:
 all functions from the Python API are also accessible from
 the Pandas API, and supplemental functions help with directly creating
 [pandas](https://pandas.pydata.org/){: target="_blank"}
 objects using data from the Data Commons knowledge graph for common
 use cases. 
 
-> **Note:** This and related pages cover [V1](/api/rest/v1) of the Pandas APIs. For V2 APIs, see [Data Commons Python API V2](/api/python/v2/)
-
 Before proceeding, make sure you have followed the setup instructions below.
 
 ## Install the Python Data Commons API

api/python/index.md

@@ -8,13 +8,13 @@ has_children: true
 
 # Data Commons Python API
 
+> **Note:** This version of the Data Commons Python API will be deprecated in early 2026. Please migrate your applications to [V2](/api/python/v2). For help on translating your requests, see the [Migration guide](/api/python/v2/migration.html).
+
 The Data Commons Python API is a Python library that enables developers to
 programmatically access nodes in the Data Commons knowledge graph. This package
 allows users to explore the structure of the graph, integrate statistics from
 the graph into data analysis workflows and much more. 
 
-> **Note:** This and related pages cover [V1](/api/rest/v1) of the Python APIs. For V2 APIs, see [Data Commons Python API V2](/api/python/v2/)
-
 Before proceeding, make sure you have followed the setup instructions below.
 
 ## Install the Python Data Commons API