docs: def describe_constant_1d(series):
      """Compute summary statistics of a constant (`S_TYPE_CONST`) variable (a Series).
  
      Parameters
      ----------
      series : Series
          The variable to describe.
  
      Returns
      -------
      Series
          The description of the variable as a Series with index being stats keys.
      """
      return pd.Series([base.S_TYPE_CONST], index=['type'], name=series.name)