code: def compile_infix_regex(entries):
      
      expression = "|".join([piece for piece in entries if piece.strip()])
      return re.compile(expression)
docs: Compile a sequence of infix rules into a regex object.
  
      entries (tuple): The infix rules, e.g. spacy.lang.punctuation.TOKENIZER_INFIXES.
      RETURNS (regex object): The regex object. to be used for Tokenizer.infix_finditer.