code: def save_filter(self):
      curr_settings = global_state.get_settings(self.data_id)
      filters_key = "{}Filters".format(
          "outlier" if self.cfg["type"] == "outliers" else "column"
      )
      curr_filters = curr_settings.get(filters_key) or {}
      fltr = self.builder.build_filter()
      if fltr is None:
          curr_filters.pop(self.column, None)
      else:
          curr_filters[self.column] = fltr
      curr_settings[filters_key] = curr_filters
      global_state.set_settings(self.data_id, curr_settings)
      return curr_filters
  
imports: import json
  import numpy
  import pandas
  import dtale.global_state
  from dtale.utils import classify_type, find_dtype, format_data, make_list
  from dtale.query import build_col_key
label_desc: Use image node_id 2 for calling the ColumnFilter obj's underlying member method code with example usage: obj.save_filter() and returns: curr_filters