docstr: Initializes the preprocessor.
  
  Args:
      start_token: Unique start token to be inserted at the beginning of the target text.
      end_token: Unique end token to be attached at the end of a target text.
      punctuation_pattern: Regex pattern for punktuation that is splitted from the tokens.
      filter_pattern: Regex pattern for characters to be removed from the text.
      add_input_start_end: Whether to add start and end token to input sequence.
      lower_case: Whether to perform lower casing.
      hash_numbers: Whether to replace numbers by a #.
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code: def __init__(
      self,
      start_token="<start>",
      end_token="<end>",
      punctuation_pattern="([!.?,])",
      filter_pattern='(["#$%&()*+/:;<=>@[\\]^_`{|}~\t\n])',
      add_input_start_end=True,
      lower_case=True,
      hash_numbers=True,
  ):
      """
      Initializes the preprocessor.
  
      Args:
          start_token: Unique start token to be inserted at the beginning of the target text.
          end_token: Unique end token to be attached at the end of a target text.
          punctuation_pattern: Regex pattern for punktuation that is splitted from the tokens.
          filter_pattern: Regex pattern for characters to be removed from the text.
          add_input_start_end: Whether to add start and end token to input sequence.
          lower_case: Whether to perform lower casing.
          hash_numbers: Whether to replace numbers by a #.
      """
      self.start_token = start_token
      self.end_token = end_token
      self.punctuation_pattern = punctuation_pattern
      self.filter_pattern = filter_pattern
      self.add_input_start_end = add_input_start_end
      self.lower_case = lower_case
      self.hash_numbers = hash_numbers
  
imports: import re
  from typing import Tuple
label_desc: Use image node_id 1 to create a new Preprocessor object  with example: obj = Preprocessor(start_token, end_token, punctuation_pattern, filter_pattern, add_input_start_end, lower_case, hash_numbers)