Return sqlalchemy connect string URI.

def uri(self):
        """
        Return sqlalchemy connect string URI.
        """
        return self.uri_template.format(
            host=self.host,
            port="" if self.port is None else self.port,
            database=self.database,
            username=self.username,
            password="" if self.password is None else self.password,
            has_password="" if self.password is None else ":",
            has_port="" if self.port is None else ":",
        )