code: def ret(eqdata, **kwargs):
      
      if 'outputcol' not in kwargs:
          kwargs['outputcol'] = 'Return'
      result = growth(eqdata, **kwargs)
      result.values[:, :] -= 1.
      return result
docs: Generate a DataFrame where the sole column, 'Return',
      is the return for the equity over the given number of sessions.
      
      For example, if 'XYZ' has 'Adj Close' of `100.0` on 2014-12-15 and 
      `90.0` 4 *sessions* later on 2014-12-19, then the 'Return' value
      for 2014-12-19 will be `-0.1`.
  
      Parameters
      ----------
      eqdata : DataFrame
          Data such as that returned by `get()`
      selection : str, optional
          Column from which to determine growth values. Defaults to
          'Adj Close'.
      n_sessions : int
          Number of sessions to count back for calculating today's
          return. For example, if `n_sessions` is set to 4, return is
          calculated relative to the price 4 sessions ago. Defaults
          to 1 (price of previous session).
      skipstartrows : int
          Rows to skip at beginning of `eqdata` in addition to the 1 row that must
          be skipped because the calculation relies on a prior data point.
          Defaults to 0.
      skipendrows : int
          Rows to skip at end of `eqdata`. Defaults to 0.
      outputcol : str, optional
          Name for column of output dataframe. Defaults to 'Return'.
  
      Returns
      ----------
      out : DataFrame
  
      See Also
      --------
      :func:`growth`
  
      Notes
      ----------
      The interval is the number of *sessions* between the 2 values
      whose ratio is being measured, *not* the number of days (which
      includes days on which the market is closed).
  
      The percentage gain or loss is measured relative to the earlier
      date, but the index date is the later date. The index is chose because
      that is the date on which the value is known. The percentage measure is because
      that is the way for calculating percent profit and loss.