code: def tube(self, radius=None, scalars=None, capping=True, n_sides=20,
               radius_factor=10, preference='point', inplace=False):
          
          if n_sides < 3:
              n_sides = 3
          tube = vtk.vtkTubeFilter()
          tube.SetInputDataObject(self)
          # User Defined Parameters
          tube.SetCapping(capping)
          if radius is not None:
              tube.SetRadius(radius)
          tube.SetNumberOfSides(n_sides)
          tube.SetRadiusFactor(radius_factor)
          # Check if scalar array given
          if scalars is not None:
              if not isinstance(scalars, str):
                  raise TypeError('Scalar array must be given as a string name')
              _, field = self.get_scalar(scalars, preference=preference, info=True)
              # args: (idx, port, connection, field, name)
              tube.SetInputArrayToProcess(0, 0, 0, field, scalars)
              tube.SetVaryRadiusToVaryRadiusByScalar()
          # Apply the filter
          tube.Update()
  
          mesh = _get_output(tube)
          if inplace:
              self.overwrite(mesh)
          else:
              return mesh
docs: Generate a tube around each input line. The radius of the tube can be
          set to linearly vary with a scalar value.
  
          Parameters
          ----------
          radius : float
              Minimum tube radius (minimum because the tube radius may vary).
  
          scalars : str, optional
              Scalar array by which the radius varies
  
          capping : bool
              Turn on/off whether to cap the ends with polygons. Default True.
  
          n_sides : int
              Set the number of sides for the tube. Minimum of 3.
  
          radius_factor : float
              Maximum tube radius in terms of a multiple of the minimum radius.
  
          preference : str
              The field preference when searching for the scalar array by name
  
          inplace : bool, optional
              Updates mesh in-place while returning nothing.
  
          Returns
          -------
          mesh : vtki.PolyData
              Tube-filtered mesh. None when inplace=True.