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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def index(cls, document, id_=None, overwrite_existing=True, es=None, index=None):
 """Adds or updates a document to the index :arg document: Python dict of key/value pairs representing the document .. Note:: This must be serializable into JSON. :arg id_: the id of the document .. Note:: If you don't provide an ``id_``, then Elasticsearch will make up an id for your document and it'll look like a character name from a Lovecraft novel. :arg overwrite_existing: if ``True`` overwrites existing documents of the same ID and doctype :arg es: The `Elasticsearch` to use. If you don't specify an `Elasticsearch`, it'll use `cls.get_es()`. :arg index: The name of the index to use. If you don't specify one it'll use `cls.get_index()`. .. Note:: If you need the documents available for searches immediately, make sure to refresh the index by calling ``refresh_index()``. """

        if es is None:
            es = cls.get_es()

        if index is None:
            index = cls.get_index()

        kw = {}
        if not overwrite_existing:
            kw['op_type'] = 'create'
        es.index(index=index, doc_type=cls.get_mapping_type_name(),
                 body=document, id=id_, **kw)