code: def test_parse_vector(self):
      a = DenseVector([])
      self.assertEqual(str(a), "[]")
      self.assertEqual(Vectors.parse(str(a)), a)
      a = DenseVector([3, 4, 6, 7])
      self.assertEqual(str(a), "[3.0,4.0,6.0,7.0]")
      self.assertEqual(Vectors.parse(str(a)), a)
      a = SparseVector(4, [], [])
      self.assertEqual(str(a), "(4,[],[])")
      self.assertEqual(SparseVector.parse(str(a)), a)
      a = SparseVector(4, [0, 2], [3, 4])
      self.assertEqual(str(a), "(4,[0,2],[3.0,4.0])")
      self.assertEqual(Vectors.parse(str(a)), a)
      a = SparseVector(10, [0, 1], [4, 5])
      self.assertEqual(
          SparseVector.parse(" (10, [0,1 ],[ 4.0,5.0] )"), a
      )
  
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 16 for calling the VectorTests obj's underlying member method code with example usage: obj.test_parse_vector() without return types