docs: def interpolate_na(self, dim=None, method='linear', limit=None,
                         use_coordinate=True,
                         **kwargs):
          """Interpolate values according to different methods.
  
          Parameters
          ----------
          dim : str
              Specifies the dimension along which to interpolate.
          method : {'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic',
                    'polynomial', 'barycentric', 'krog', 'pchip',
                    'spline'}, optional
              String indicating which method to use for interpolation:
  
              - 'linear': linear interpolation (Default). Additional keyword
                arguments are passed to ``numpy.interp``
              - 'nearest', 'zero', 'slinear', 'quadratic', 'cubic',
                'polynomial': are passed to ``scipy.interpolate.interp1d``. If
                method=='polynomial', the ``order`` keyword argument must also be
                provided.
              - 'barycentric', 'krog', 'pchip', 'spline': use their respective
                ``scipy.interpolate`` classes.
          use_coordinate : boolean or str, default True
              Specifies which index to use as the x values in the interpolation
              formulated as `y = f(x)`. If False, values are treated as if
              eqaully-spaced along `dim`. If True, the IndexVariable `dim` is
              used. If use_coordinate is a string, it specifies the name of a
              coordinate variariable to use as the index.
          limit : int, default None
              Maximum number of consecutive NaNs to fill. Must be greater than 0
              or None for no limit.
  
          Returns
          -------
          Dataset
  
          See also
          --------
          numpy.interp
          scipy.interpolate
          """
          from .missing import interp_na, _apply_over_vars_with_dim
  
          new = _apply_over_vars_with_dim(interp_na, self, dim=dim,
                                          method=method, limit=limit,
                                          use_coordinate=use_coordinate,
                                          **kwargs)
          return new