code: def _match_field(field_value, pattern, ignore_case=False, normalize_values=False):
  	
  
  	if normalize_values:
  		ignore_case = True
  
  	normalize = normalize_value if normalize_values else lambda x: str(x)
  	search = functools.partial(re.search, flags=re.I) if ignore_case else re.search
  
  	# audio_metadata fields contain a list of values.
  	if isinstance(field_value, list):
  		return any(search(pattern, normalize(value)) for value in field_value)
  	else:
  		return search(pattern, normalize(field_value))
docs: Match an item metadata field value by pattern.
  
  	Note:
  		Metadata values are lowercased when ``normalized_values`` is ``True``,
  		so ``ignore_case`` is automatically set to ``True``.
  
  	Parameters:
  		field_value (list or str): A metadata field value to check.
  		pattern (str): A regex pattern to check the field value(s) against.
  		ignore_case (bool): Perform case-insensitive matching.
  			Default: ``False``
  		normalize_values (bool): Normalize metadata values to remove common differences between sources.
  			Default: ``False``
  
  	Returns:
  		bool: True if matched, False if not.