<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def update_security_group(self, security_group, body=None):
 """Updates a security group."""

        return self.put(self.security_group_path %
                        security_group, body=body)