code: def build_aggs(y, z=None, agg=None, extended_aggregation=[]):
      z_exists = len(make_list(z))
      agg_cols = make_list(y)
      if z_exists:
          agg_cols = make_list(z)
  
      aggs = {}
      if not len(extended_aggregation or []):
          aggs[agg] = agg_cols
      else:
          for ext_agg in extended_aggregation:
              aggs[ext_agg["agg"]] = aggs.get(ext_agg["agg"], []) + [
                  ext_agg["col"]
              ]
      return aggs
  
imports: import copy
  import numpy
  import pandas
  import dtale.global_state
  import dtale.pandas_util
  from dtale.column_analysis import handle_cleaners
  from dtale.constants import CHART_JOINER_CHAR
  from dtale.query import build_col_key, run_query
  from dtale.utils import ChartBuildingError, build_formatters, classify_type, find_dtype, find_dtype_formatter, flatten_lists, get_dtypes, json_int, make_list, triple_quote
label_desc: Use image node_id 11 for calling a global function with example usage: build_aggs(y, z, agg, extended_aggregation) and returns: aggs