https://python.langchain.com/v0.2/docs/integrations/toolkits/openapi/#1st-example-hierarchical-planning-agent with https://api.python.langchain.com/en/latest/agent_toolkits/langchain_community.agent_toolkits.openapi.spec.ReducedOpenAPISpec.html#langchain_community.agent_toolkits.openapi.spec.ReducedOpenAPISpec and https://api.python.langchain.com/en/latest/_modules/langchain_community/agent_toolkits/openapi/spec.html#ReducedOpenAPISpec as source code.