This notebook goes over how to use Langchain with YandexGPT embeddings models. To use, you should have the yandexcloud python package installed. 
%pip install --upgrade --quiet  yandexcloud
First, you should create service account with the ai.languageModels.user role. Next, you have two authentication options:
  • IAM token. You can specify the token in a constructor parameter iam_token or in an environment variable YC_IAM_TOKEN.
  • API key You can specify the key in a constructor parameter api_key or in an environment variable YC_API_KEY.
To specify the model you can use model_uri parameter, see the documentation for more details. By default, the latest version of text-search-query is used from the folder specified in the parameter folder_id or YC_FOLDER_ID environment variable. 
from langchain_community.embeddings.yandex import YandexGPTEmbeddings

embeddings = YandexGPTEmbeddings()

text = "This is a test document."

query_result = embeddings.embed_query(text)

doc_result = embeddings.embed_documents([text])

query_result[:5]

[-0.021392822265625,
 0.096435546875,
 -0.046966552734375,
 -0.0183258056640625,
 -0.00555419921875]

doc_result[0][:5]

[-0.021392822265625,
 0.096435546875,
 -0.046966552734375,
 -0.0183258056640625,
 -0.00555419921875]