human
Solve the following python programming problem given the following code:
@ wsgi.response (200) 
def update(self, req, body, gid, securitygroup_id) : 
    def _validate(body, gid, securitygroup_id) : 
        if (not self.is_valid_body (body, 'securitygroup')) : 
            msg = _ ('Invalid request body') 
            raise exception.InvalidInput (reason = msg) 
self._uuid_check (gid, securitygroup_id) 
        values = body ['securitygroup'] 
        is_default = values.get ('is_default') 
        if (is_default is not None) : 
            try : 
                is_default = strutils.bool_from_string (is_default, strict = True) 
except ValueError : 
                msg = _ ('is_default must be a boolean') 
                raise exception.InvalidInput (reason = msg) 
else : 
            msg = _ ('SecurityGroup is_default is required') 
            raise exception.InvalidInput (reason = msg) 
valid_values = { 
            
} 
        valid_values ['is_default'] = is_default 
        return valid_values 
try : 
        values = _validate (body, gid, securitygroup_id) 
        context = req.environ ['rack.context'] 
        securitygroup = db.securitygroup_update (context, gid, securitygroup_id, values) 
except exception.InvalidInput as exc : 
        raise webob.exc.HTTPBadRequest (explanation = exc.format_message ()) 
except exception.NotFound as exc : 
        raise webob.exc.HTTPNotFound (explanation = exc.format_message ()) 
return self._view_builder.update (context) 

    
    

    Fix the buggy line: return self._view_builder.update (context)
assistant
#Here is Python code to fix the buggy line: return self.

return self._view_builder.update (securitygroup)