code: def test_per_array_sequence_dict_creation(self):
      # Create a PerArraySequenceDict object using another
      # PerArraySequenceDict object.
      total_nb_rows = DATA["tractogram"].streamlines.total_nb_rows
      data_per_point = DATA["tractogram"].data_per_point
      data_dict = PerArraySequenceDict(total_nb_rows, data_per_point)
      assert data_dict.keys() == data_per_point.keys()
      for k in data_dict.keys():
          assert_arrays_equal(data_dict[k], data_per_point[k])
  
      del data_dict["fa"]
      assert len(data_dict) == len(data_per_point) - 1
  
      # Create a PerArraySequenceDict object using an existing dict object.
      data_per_point = DATA["data_per_point"]
      data_dict = PerArraySequenceDict(total_nb_rows, data_per_point)
      assert data_dict.keys() == data_per_point.keys()
      for k in data_dict.keys():
          assert_arrays_equal(data_dict[k], data_per_point[k])
  
      del data_dict["fa"]
      assert len(data_dict) == len(data_per_point) - 1
  
      # Create a PerArraySequenceDict object using keyword arguments.
      data_per_point = DATA["data_per_point"]
      data_dict = PerArraySequenceDict(total_nb_rows, **data_per_point)
      assert data_dict.keys() == data_per_point.keys()
      for k in data_dict.keys():
          assert_arrays_equal(data_dict[k], data_per_point[k])
  
      del data_dict["fa"]
      assert len(data_dict) == len(data_per_point) - 1
  
imports: import copy
  import operator
  import sys
  import unittest
  import warnings
  from collections import defaultdict
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from ...testing import assert_arrays_equal, clear_and_catch_warnings
  from ..None import tractogram
  from ..tractogram import LazyDict, LazyTractogram, PerArrayDict, PerArraySequenceDict, Tractogram, TractogramItem, is_data_dict, is_lazy_dict
label_desc: Use image node_id 1 for calling the TestPerArraySequenceDict obj's underlying member method code with example usage: obj.test_per_array_sequence_dict_creation() without return types