code: def append_columns(self, names):
      self._columns = self._columns.append(pd.Index(names))
      # TODO: extend anonymous column
      anonymous_generator = AnonymousGenerator(
          site_name=self._anonymous_summary["site_name"]
      )
  
      (
          anonymous_columns,
          anonymous_summary,
      ) = anonymous_generator.add_anonymous_columns(
          names, self._anonymous_summary
      )
      self._anonymous_columns = self._anonymous_columns.append(
          pd.Index(anonymous_columns)
      )
      self._anonymous_summary = anonymous_summary
  
imports: import copy
  from typing import List, Union
  import pandas
  from .utils import AnonymousGenerator
label_desc: Use image node_id 20 for calling the Schema obj's underlying member method code with example usage: obj.append_columns(names) without return types