Normalize a given string to fit the data it contains, like simple test, or email to a password

normalize_str.py

def normalize(obj, dict_key=None, regx="text"):
    """ This function cleans and normalize a given string. It performs three
        main operations: Sets to lower case, strips any trailing whitespace and
        finally substracts any character that isn't allowed in the string type
        regex, the character is replaced with an empty string.

        :param obj: this object can be 'str' or 'dict' instance type.
        :type obj:str It performs a directly normalization
        :type obj:dict It expects a key ( from 'dict_key' arg ) string
            to extract the string to be normalize, otherwise returns None.

        :type dict_key:str
        :param dict_key: The dictionary key to extract a string.

        :type regx:str
        :param regx: it defines the type of substraction to be performed
            in the string. By default it is set the 'text' type.

            ... string types ( Regex )

                - text: alphanumerical ( ascii ) & non-ascii ( á é í ó ú ñ )
                - usrname: alphanumerical ( ascii ) & special ( _ )
                - email: alphanumerical ( ascii ) & special ( @ - . _ )
                - pwd: alphanumerical ( ascii ) & special ( - . _ $ & # )
                - num: only numerical ( 0 - 9 )

        :return the normalized string, otherwise returns None
    """
    regxs = {
        "text": ("[^A-Za-z0-9áéíóúñ]+", " "),
        "usrname": ("[^A-Za-z0-9_]+", ""),
        "email": ("[^A-Za-z0-9@\-_.]+", ""),
        "pwd": ("[^A-Za-z0-9@$&#\-_.]+", ""),
        "num": ("[^0-9]+", "")
    }

    try:
        rkey = regxs[regx][0]
        rsub = regxs[regx][1]

        if isdictionary(value):
            obj = obj.get(dict_key)

        obj = text_type(obj).lower().strip()
        obj = re.sub(re.compile(rkey), rsub, obj)
    except:
        obj = None
    return obj

it is buggy!