code: def test_normalize_spaces():
      strings = cudf.Series(
          [
              " the\t quick fox  jumped over the lazy dog",
              "the siamésé cat\f jumped\t\tunder the sofa  ",
              None,
              "",
          ]
      )
      expected = cudf.Series(
          [
              "the quick fox jumped over the lazy dog",
              "the siamésé cat jumped under the sofa",
              None,
              "",
          ]
      )
  
      actual = strings.str.normalize_spaces()
  
      assert type(expected) == type(actual)
      assert_eq(expected, actual)
  
imports: import random
  import string
  import numpy
  import pytest
  import cudf
  from cudf.core.byte_pair_encoding import BytePairEncoder
  from cudf.core.tokenize_vocabulary import TokenizeVocabulary
  from cudf.testing._utils import assert_eq
label_desc: Use image node_id 6 for calling a global function with example usage: test_normalize_spaces() without return types