'string is not a function'

Getting this error likely because I've formatted the conditional check incorrectly. I'm checking to see if the last page visited was 'leave'. If so, show Text, otherwise, show Other text. What's the correct syntax?

This is currently incorrect:

<% if (story.checkpointName() == 'leave'){ %>
Text
<% } else { %>
Other text
<% } %>

So would it be:

<% if (story.checkpointName('leave')){ %>
Text
<% } else { %>
Other text
<% } %>

Or:

<% if (Story.checkpointName('leave')){ %>
Text
<% } else { %>
Other text
<% } %>

Or something entirely different? I'm stumped even after browsing the commented source.