old_contents: """Latex parsing functionality
  
  This module provides functions to parse latex text
  """
  
  import re
  
  ######################################################################
  # Latex escape regex constants
  ######################################################################
  
  # Organize all latex escape characters in one list
  # (EXCEPT FOR ( "\" ), which is handled separately)
  # escaping those which are special characters in
  # PERL regular expressions
  ESCAPE_CHARS = [r'\&', '%', r'\$', '#', '_', r'\{', r'\}', '~', r'\^', ]
  
  # For each latex escape character, create a regular expression
  # that matches all of the following criteria
  # 1) one or two characters
  # 2) if two characters, the first character is NOT a backslash ( "\" )
  # 3) if two characters, the second, if one, the first character
  #       is one of the latex escape characters
  REGEX_ESCAPE_CHARS = [
          (re.compile(r"(?<!\\)" + i), r"\\" + i.replace('\\', ''))
          for i in ESCAPE_CHARS
          ]
  
  # Place escape characters in [] for "match any character" regex
  ESCAPE_CHARS_OR = r'[{}\\]'.format(''.join(ESCAPE_CHARS))
  
  # For the back slash, create a regular expression
  # that matches all of the following criteria
  # 1) three characters
  # 2) the first character is not a backslash
  # 3) the second characters is a backslash
  # 4) the third character is none of the ESCAPE_CHARS,
  #       and is also not a backslash
  REGEX_BACKSLASH = re.compile(r'(?<!\\)\\(?!{})'.format(ESCAPE_CHARS_OR))
  
  ######################################################################
  # Declare module functions
  ######################################################################
  def escape_latex_str(string_text):
      '''Escape a latex string'''
      for regex, replace_text in REGEX_ESCAPE_CHARS:
          string_text = re.sub(regex, replace_text, string_text)
      string_text = re.sub(REGEX_BACKSLASH, r'\\\\', string_text)
      return string_text
  
new_contents: """Latex parsing functionality
  
  This module provides functions to parse latex text
  """
  
  import re
  
  ######################################################################
  # Latex escape regex constants
  ######################################################################
  
  # Organize all latex escape characters in one list
  # (EXCEPT FOR ( "\" ), which is handled separately)
  # escaping those which are special characters in
  # PERL regular expressions
  ESCAPE_CHARS = [r'\&', '%', r'\$', '#', '_', r'\{', r'\}', '~', r'\^', ]
  
  # For each latex escape character, create a regular expression
  # that matches all of the following criteria
  # 1) one or two characters
  # 2) if two characters, the first character is NOT a backslash ( "\" )
  # 3) if two characters, the second, if one, the first character
  #       is one of the latex escape characters
  REGEX_ESCAPE_CHARS = [
          (re.compile(r"(?<!\\)" + i), r"\\" + i.replace('\\', ''))
          for i in ESCAPE_CHARS
          ]
  
  # Place escape characters in [] for "match any character" regex
  ESCAPE_CHARS_OR = r'[{}\\]'.format(''.join(ESCAPE_CHARS))
  
  # For the back slash, create a regular expression
  # that matches all of the following criteria
  # 1) one, two, or three characters
  # 2) the first character is not a backslash
  # 3) the second character is a backslash
  # 4) the third character is none of the ESCAPE_CHARS,
  #       and is also not a backslash
  REGEX_BACKSLASH = re.compile(r'(?<!\\)\\(?!{})'.format(ESCAPE_CHARS_OR))
  
  ######################################################################
  # Declare module functions
  ######################################################################
  def escape_latex_str(string_text):
      '''Escape a latex string'''
      for regex, replace_text in REGEX_ESCAPE_CHARS:
          string_text = re.sub(regex, replace_text, string_text)
      string_text = re.sub(REGEX_BACKSLASH, r'\\\\', string_text)
      return string_text
  
subject: Revise spelling of comment