def refresh_schema(self) -> None:
        """
        Refresh schema.

        Example data of self.structured_schema
        {
            "node_props": {
                "Person": [
                    {"property": "name", "type": "STRING", "comment": "The name of the person"},
                    {"property": "age", "type": "INTEGER", "comment": "The age of the person"},
                    {"property": "dob", "type": "DATE", "comment": "The date of birth of the person"}
                ],
                "Company": [
                    {"property": "name", "type": "STRING", "comment": "The name of the company"},
                    {"property": "founded", "type": "DATE", "comment": "The date of foundation of the company"}
                ]
            },
            "rel_props": {
                "WORKS_AT": [
                    {"property": "since", "type": "DATE", "comment": "The date when the person started working at the company"}
                ],
                "MANAGES": [
                    {"property": "since", "type": "DATE", "comment": "The date when the person started managing the company"}
                ]
            },
            "relationships": [
                {"start": "Person", "type": "WORKS_AT", "end": "Company"},
                {"start": "Person", "type": "MANAGES", "end": "Company"}
            ]
        }
        """
        tags_schema = {}
        edge_types_schema = {}
        relationships = []

        for node_label in self.structured_query(
            "MATCH ()-[node_label:`__meta__node_label__`]->() "
            "RETURN node_label.label AS name, "
            "JSON_EXTRACT(node_label.props_json) AS props"
        ):
            tags_schema[node_label["name"]] = []
            # TODO: add properties to tags_schema

        for rel_label in self.structured_query(
            "MATCH ()-[rel_label:`__meta__rel_label__`]->() "
            "RETURN rel_label.label AS name, "
            "src(rel_label) AS src, dst(rel_label) AS dst, "
            "JSON_EXTRACT(rel_label.props_json) AS props"
        ):
            edge_types_schema[rel_label["name"]] = []
            # TODO: add properties to edge_types_schema
            relationships.append(
                {
                    "start": rel_label["src"],
                    "type": rel_label["name"],
                    "end": rel_label["dst"],
                }
            )

        self.structured_schema = {
            "node_props": tags_schema,
            "rel_props": edge_types_schema,
            "relationships": relationships,
            # TODO: need to check necessarity of meta data here
        }

        Refresh schema.

        Example data of self.structured_schema
        {
            "node_props": {
                "Person": [
                    {"property": "name", "type": "STRING", "comment": "The name of the person"},
                    {"property": "age", "type": "INTEGER", "comment": "The age of the person"},
                    {"property": "dob", "type": "DATE", "comment": "The date of birth of the person"}
                ],
                "Company": [
                    {"property": "name", "type": "STRING", "comment": "The name of the company"},
                    {"property": "founded", "type": "DATE", "comment": "The date of foundation of the company"}
                ]
            },
            "rel_props": {
                "WORKS_AT": [
                    {"property": "since", "type": "DATE", "comment": "The date when the person started working at the company"}
                ],
                "MANAGES": [
                    {"property": "since", "type": "DATE", "comment": "The date when the person started managing the company"}
                ]
            },
            "relationships": [
                {"start": "Person", "type": "WORKS_AT", "end": "Company"},
                {"start": "Person", "type": "MANAGES", "end": "Company"}
            ]
        }
        
llama-index-integrations/graph_stores/llama-index-graph-stores-nebula/llama_index/graph_stores/nebula/nebula_property_graph.py