'Initialize recompilable regex value.
Args:
attribute: Attribute validator associated with this regex value.
value: Initial underlying python value for regex string.  Either a single
regex string or a list of regex strings.
key: Name of the field.'

def __init__(self, attribute, value, key):

    self.__attribute = attribute
    self.__value = value
    self.__regex = None
    self.__key = key
