Get CEll Types and node_ids tuple for each cell in vtkUnstructuredGrid instance (python ,vtk)

Question

I want to get cell types ('Hexa','tetra',etc) and node ids tuples (or arrays) for each cell using library vtk in python in vtkUnstructuredGrid instance. I dont understand how to do this operation. Earlier I had used meshio library and it was very easy operation. now But I need use library vtk.

import os
try:
    from paraview.simple import (
    OpenDataFile,
    servermanager,
    FrequencyAnalysis)
    from paraview import vtk
    from paraview.vtk.util.numpy_support import numpy_to_vtk, vtk_to_numpy
except ImportError as error:
    print('import paraview error')
BASE_DIR = os.getcwd()
JOIN = os.path.join
file_name = 'for_meshio_library.pvd'
reader = OpenDataFile(JOIN(BASE_DIR,file_name)) 
dataReader = servermanager.Fetch(reader) # VtustrictureGrid instance in PARAVIEW
pointData = dataReader.GetPointData()
#cellData = dataReader.GetCellData()
point_data = dataReader.GetPointData()
node_ids = point_data.GetArray('Node ID') 
node_ids_to_numpy_array  = vtk_to_numpy(node_ids)  
nodes_count = len(node_ids_to_numpy_array)
points = dataReader.GetPoints()
for index in range(nodes_count):
    print(points.GetPoint(index))
cells =  dataReader.GetCells() # ?????????????????????????????????????????????????