'Required:
field_name --the fist
field_name -- the first word in the string
name --the changed name according to the dictionary
line -- the string to be parse
Returns:
list of None, None, and part of a tag
Logic:'

def __date_func(self, field_name, name, line):

    the_string = name
    match_group = re.search(self.__date_exp, line)
    if match_group:
        the_string += ('<date-format>%s' % match_group.group(1))
    return [None, None, the_string]
