Find a security group by name.

        Returns a :class:`EC2SecGroup` instance if found, otherwise returns
        None.

def find_secgroup(self, name):
        """
        Find a security group by name.

        Returns a :class:`EC2SecGroup` instance if found, otherwise returns
        None.

        """
        res = self.ec2.get_all_security_groups(filters={'group-name': name})
        if res:
            return EC2SecGroup(res[0])