<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_link(self, rel):
 """ Return link for specified resource """

        if rel in self.links:
            return self.links[rel]
        raise ResourceNotFound('Resource requested: %r is not available '
            'on this element.' % rel)