code: def flatten_columns(df, columns=None):
      if columns is not None:
          return [
              " ".join(
                  [
                      "{}-{}".format(c1, str(c2))
                      for c1, c2 in zip(
                          make_list(columns), make_list(col_val)
                      )
                  ]
              ).strip()
              for col_val in df.columns.values
          ]
      return [
          " ".join([str(c) for c in make_list(col)]).strip()
          for col in df.columns.values
      ]
  
imports: import pandas
  from scipy import stats
  import dtale.global_state
  import dtale.pandas_util
  from dtale.query import run_query
  from dtale.utils import make_list
label_desc: Use image node_id 1 for calling a global function with example usage: flatten_columns(df, columns) and returns: unknown, unknown