code: def build_index(self, angular=False, n_trees=None):
      # builds local index
      self.assert_fitted()
      self.assert_features_line_up_with_nodes()
      X = self._get_feature("nodes")
      self.search_index = FaissVectorSearch(X.values)
  
file_path: pygraphistry/graphistry/text_utils.py
imports: import pandas
  from .feature_utils import FeatureMixin
  from .ai_utils import search_to_df, FaissVectorSearch
  from .constants import WEIGHT, DISTANCE
  from logging import getLogger
  from typing import TYPE_CHECKING
label_desc: Use image node_id 4 for calling the SearchToGraphMixin obj's underlying member method code with example usage: obj.build_index(angular, n_trees) without return types