def _create_metadata_index_fields(self) -> List[Any]:
        """Create a list of index fields for storing metadata values."""
        from azure.search.documents.indexes.models import SimpleField

        index_fields = []

        # create search fields
        for v in self._metadata_to_index_field_map.values():
            field_name, field_type = v

            # Skip if the field is already mapped
            if field_name in self._field_mapping.values():
                continue

            if field_type == MetadataIndexFieldType.STRING:
                index_field_type = "Edm.String"
            elif field_type == MetadataIndexFieldType.INT32:
                index_field_type = "Edm.Int32"
            elif field_type == MetadataIndexFieldType.INT64:
                index_field_type = "Edm.Int64"
            elif field_type == MetadataIndexFieldType.DOUBLE:
                index_field_type = "Edm.Double"
            elif field_type == MetadataIndexFieldType.BOOLEAN:
                index_field_type = "Edm.Boolean"
            elif field_type == MetadataIndexFieldType.COLLECTION:
                index_field_type = "Collection(Edm.String)"

            field = SimpleField(
                name=field_name,
                type=index_field_type,
                filterable=True,
                hidden=field_name in self._hidden_field_keys,
            )
            index_fields.append(field)

        return index_fields
Create a list of index fields for storing metadata values.
llama-index-integrations/vector_stores/llama-index-vector-stores-azureaisearch/llama_index/vector_stores/azureaisearch/base.py