code: def vector_store_type(self, tree):
      vector_store_type = None
      token = tree.children[1]
  
      if str.upper(token) == "FAISS":
          vector_store_type = VectorStoreType.FAISS
      elif str.upper(token) == "QDRANT":
          vector_store_type = VectorStoreType.QDRANT
      elif str.upper(token) == "PINECONE":
          vector_store_type = VectorStoreType.PINECONE
      elif str.upper(token) == "PGVECTOR":
          vector_store_type = VectorStoreType.PGVECTOR
      elif str.upper(token) == "CHROMADB":
          vector_store_type = VectorStoreType.CHROMADB
      elif str.upper(token) == "WEAVIATE":
          vector_store_type = VectorStoreType.WEAVIATE
      elif str.upper(token) == "MILVUS":
          vector_store_type = VectorStoreType.MILVUS
      return vector_store_type
  
imports: from lark import Tree
  from evadb.catalog.catalog_type import ColumnType, NdArrayType, VectorStoreType
  from evadb.expression.tuple_value_expression import TupleValueExpression
  from evadb.parser.create_index_statement import CreateIndexStatement
  from evadb.parser.create_statement import ColConstraintInfo, ColumnDefinition, CreateDatabaseStatement, CreateJobStatement, CreateTableStatement
  from evadb.parser.table_ref import TableRef
  from evadb.parser.types import ColumnConstraintEnum
label_desc: Use image node_id 2 for calling the CreateIndex obj's underlying member method code with example usage: obj.vector_store_type(tree) and returns: vector_store_type