class_docstr: Determines the number of unique words in a string.
  
  Description:
      Determines the number of unique words in a given string. Includes options for
      case-insensitive behavior.
  
  Args:
      case_insensitive (bool, optional): Specify case_insensitivity when searching for unique words.
      For example, setting this to True would mean "WORD word" would be treated as having
      one unique word. Defaults to False.
  
  Examples:
      >>> x = ['Word word Word', 'This is a SENTENCE.', 'green red green']
      >>> number_of_unique_words = NumberOfUniqueWords()
      >>> number_of_unique_words(x).tolist()
      [2, 4, 2]
  
      >>> x = ['word WoRD WORD worD', 'dog dog dog', 'catt CAT caT']
      >>> number_of_unique_words = NumberOfUniqueWords(case_insensitive=True)
      >>> number_of_unique_words(x).tolist()
      [1, 1, 2]
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code: def __init__(self, case_insensitive=False):
      self.case_insensitive = case_insensitive
  
file_path: featuretools/featuretools/primitives/standard/transform/natural_language/number_of_unique_words.py
imports: from string import punctuation
  from typing import Iterable
  import pandas
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import IntegerNullable, NaturalLanguage
  from featuretools.primitives.base import TransformPrimitive
  from featuretools.primitives.standard.transform.natural_language.constants import DELIMITERS
label_desc: Use image node_id 1 to create a new NumberOfUniqueWords object from inherited base classes: TransformPrimitive with example: obj = NumberOfUniqueWords(case_insensitive)