code: def test_hash(self):
      v1 = DenseVector([0.0, 1.0, 0.0, 5.5])
      v2 = SparseVector(4, [(1, 1.0), (3, 5.5)])
      v3 = DenseVector([0.0, 1.0, 0.0, 5.5])
      v4 = SparseVector(4, [(1, 1.0), (3, 2.5)])
      self.assertEqual(hash(v1), hash(v2))
      self.assertEqual(hash(v1), hash(v3))
      self.assertEqual(hash(v2), hash(v3))
      self.assertFalse(hash(v1) == hash(v4))
      self.assertFalse(hash(v2) == hash(v4))
  
imports: import array
  import unittest
  from numpy import array, array_equal, zeros, arange, tile, ones, inf
  import pyspark.ml.linalg
  from pyspark.serializers import CPickleSerializer
  from pyspark.mllib.linalg import Vector, SparseVector, DenseVector, VectorUDT, _convert_to_vector, DenseMatrix, SparseMatrix, Vectors, Matrices, MatrixUDT
  from pyspark.mllib.linalg.distributed import RowMatrix, IndexedRowMatrix, IndexedRow
  from pyspark.mllib.regression import LabeledPoint
  from pyspark.sql import Row
  from pyspark.testing.mllibutils import MLlibTestCase
  from pyspark.testing.utils import have_scipy
label_desc: Use image node_id 5 for calling the VectorTests obj's underlying member method code with example usage: obj.test_hash() without return types