Convenience method that provides a quick way to add an email grant to a
        key. This method retrieves the current ACL, creates a new grant based on
        the parameters passed in, adds that grant to the ACL and then PUT's the
        new ACL back to GS.

        :type permission: string
        :param permission: The permission being granted. Should be one of:
            READ|FULL_CONTROL
            See http://code.google.com/apis/storage/docs/developer-guide.html#authorization
            for more details on permissions.

        :type email_address: string
        :param email_address: The email address associated with the Google
                              account to which you are granting the permission.

def add_email_grant(self, permission, email_address):
        """
        Convenience method that provides a quick way to add an email grant to a
        key. This method retrieves the current ACL, creates a new grant based on
        the parameters passed in, adds that grant to the ACL and then PUT's the
        new ACL back to GS.

        :type permission: string
        :param permission: The permission being granted. Should be one of:
            READ|FULL_CONTROL
            See http://code.google.com/apis/storage/docs/developer-guide.html#authorization
            for more details on permissions.

        :type email_address: string
        :param email_address: The email address associated with the Google
                              account to which you are granting the permission.
        """
        acl = self.get_acl()
        acl.add_email_grant(permission, email_address)
        self.set_acl(acl)