What is the Elasticsearch-py equivalent to alias actions?

To implement that you need to use elasticsearch-py:

from elasticsearch import Elasticsearch
es = Elasticsearch()

# use es.indices instead of instantiating IndicesClient
es.indices.put_alias(index='tweets_1', name='tweets_search')
es.indices.put_alias(index='tweets_1', name='tweets_index')

es.indices.update_aliases({
  "actions": [
    { "add":    { "index": "tweets_2", "alias": "tweets_search" }}, 
    { "remove": { "index": "tweets_1", "alias": "tweets_index"  }}, 
    { "add":    { "index": "tweets_2", "alias": "tweets_index"  }}  
  ]
})