minor cleanup

mne/stats/cluster_level.py

@@ -1878,18 +1878,18 @@ def cluster_test(
  raise ValueError("for paired t-test, each subject must have 2 observations")
 
  # extract the data from the dataframe
- outer_func = np.concatenate if is_epo or is_arr else np.array
+ outer_func = np.concatenate if is_epo else np.array
  axes = (-3, -1) if is_tfr else (-2, -1)
 
+ def func_arr(series):
+ return np.concatenate(series.values)
+
  def func_mne(series):
  return outer_func(
  series.map(lambda inst: inst.get_data().swapaxes(*axes)).to_list()
  )
 
- def func_array(series):
- return outer_func(series.values)
-
- func = func_array if is_arr else func_mne
+ func = func_arr if is_arr else func_mne
 
  # convert to a list-like X for clustering
  X = df.groupby(iv_name).agg({dv_name: func})[dv_name].to_list()