def _execute(self, handler, *args, **kwargs):
<EOL>result = None<EOL>exc_info = None<EOL>try:<EOL><INDENT>result = handler(*args, **kwargs)<EOL><DEDENT>except Exception:<EOL><INDENT>exc_info = sys.exc_info()<EOL><DEDENT>if exc_info:<EOL><INDENT>return exc_info<EOL><DEDENT>return result<EOL>
executes one callback function