code: def _get_window(self, other=None):
          
          axis = self.obj._get_axis(self.axis)
          length = len(axis) + (other is not None) * len(axis)
  
          other = self.min_periods or -1
          return max(length, other)
docs: Get the window length over which to perform some operation.
  
          Parameters
          ----------
          other : object, default None
              The other object that is involved in the operation.
              Such an object is involved for operations like covariance.
  
          Returns
          -------
          window : int
              The window length.