Normalize email

normalize_email.py

    def normalize_email(self, email):
        """
        Normalazing email addres. An email address
        has following properties:
        1) It is case-insensitive
        2) "." characters on username part of email address is ommited.
        For instance [email protected] and [email protected] are the
        same address.
        3) Anything after "+" sign is ommited. [email protected] and
        [email protected] are same email address.

        This code does not really validate email address. Make sure given
        string is a valid email address before using this.

        If You are using django you can use
        django.core.validators.validate_email
        for validation.
        """
        # remove spaces at start and end of the and lowercase email address
        email = email.strip().lower()
        # split email into username and domain information
        username, domain = .split('@')
        # remove . characters from username
        username = username.replace('.', '')
        #remove everything after +
        username = username.split('+')[0]

        return "%s@%s" % (username, domain)

Regarding rule #2: This only applies to gmail.com/googlemail.com, just in case someone comes across this