def __get_part_date(self, part=''):
        '''
        Retrieves date of the combo part from the file
            :param part: Part of the combo file (parsed out whole SAR file
                from the combo
            :type part: str.
            :return: string containing date in ISO format (YYY-MM-DD)
        '''
        if (type(part) is not StringType):
            # We can cope with strings only
            return False

        firstline = part.split("\n")[0]

        info = firstline.split()
        datevalue = ''

        try:
            datevalue = info[3]

        except KeyError:
            datevalue = False

        except:
            traceback.print_exc()
            datevalue = False

        return(datevalue)