def search_in_line(line, pattern):
	""" Splits string line by patterns.
	Pattern MUST be compiled regexp and MUST contain enclosing parenthesis.
	Returns list of strings, always odd number of element and pattern matches are at odd positions.
	If there were no occurences, returns None.
	"""
	matches = pattern.split(line)
	if len(matches) <= 1:
		return None
	return matches