code: def mean_sdl(series, mult=2):
      """
      Mean +/- a constant times the standard deviation
  
      Parameters
      ----------
      series : pandas.Series
          Values
      mult : float
          Multiplication factor.
      """
      m = series.mean()
      s = series.std()
      return pd.DataFrame(
          {"y": [m], "ymin": m - mult * s, "ymax": m + mult * s}
      )
  
file_path: plotnine/plotnine/stats/stat_summary.py
imports: import numpy
  import pandas
  from .._utils import get_valid_kwargs, uniquecols
  from ..doctools import document
  from ..exceptions import PlotnineError
  from .stat import stat
label_desc: Use image node_id 4 for calling a global function with example usage: mean_sdl(series, mult) and returns: pd